Lactone-containing compound, polymer, resist composition, and patterning process

ABSTRACT

Lactone-containing compounds having formula (1) are novel wherein R 1  is H, F, methyl or trifluoromethyl, R 2  and R 3  are monovalent hydrocarbon groups, or R 2  and R 3  may together form an aliphatic hydrocarbon ring, R 4  is H or CO 2 R 5 , R 5  is a monovalent hydrocarbon group, W is CH 2 , O or S, and k 1  is 0 or 1. They are useful as monomers to produce polymers which are transparent to radiation≦500 nm. Radiation-sensitive resist compositions comprising the polymers as base resin exhibit excellent properties including resolution, pattern edge roughness, pattern density dependency and exposure margin.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application No. 2006-206233 filed in Japan on Jul. 28, 2006,the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

This invention relates to (1) novel lactone-containing compounds usefulas raw materials for the synthesis of functional materials,pharmaceutical and agricultural chemicals, (2) polymers comprisingrecurring units derived from the lactone-containing compounds, (3)resist compositions comprising the polymers, and (4) a patterningprocess using the resist compositions.

BACKGROUND ART

The recent drive for higher integration and operating speeds in LSIdevices makes it necessary to further reduce the pattern rule.Deep-ultraviolet lithography was developed as an essential technologyfor micropatterning to a feature size of 0.3 μm or less. Among others,the KrF excimer laser lithography has been fully recognized as acommercial scale production technology.

With respect to chemically amplified resist compositions adapted for thephotolithography using ArF excimer laser light of 193 nm wavelength as alight source, the primary requirement is, of course, a high transparencyat that wavelength. They are also required to meet a high etchresistance sufficient to comply with film thickness reduction, a highsensitivity sufficient to minimize the burden to expensive opticalmaterials, and among others, a high resolution sufficient to form anexact fine pattern. The key toward these requirements is to develop abase resin featuring high transparency, high rigidity and highreactivity. Active efforts have been devoted for such development.

Typical resins known to be highly transparent to ArF excimer laser lightare copolymers of acrylic or methacrylic acid derivatives as disclosedin JP-A 4-39665.

One of the (meth)acrylic resins proposed thus far is a combination of(meth)acrylic units having methyladamantane ester as acid labile groupunits with (meth)acrylic units having lactone ring ester as adhesivegroup units as disclosed in JP-A 9-90637. Acid labile groups of exo formare described in U.S. Pat. No. 6,448,420 (JP-A 2000-327633). Thesegroups have so high an acid elimination ability and require a low levelof activation energy for acid elimination, affording a high resolutionand low dependence on post-exposure bake (PEB). Norbornane lactone isalso proposed as an adhesive group having enhanced etching resistance asdisclosed in JP-A 2000-26446 and JP-A 2000-159758. These studies haveachieved significant improvements in the resolution of ArF resists.

However, in an attempt to form a fine pattern having a pitch of lessthan 200 nm, prior art resist materials are difficult to form patternsand the patterns, if formed, have insufficient rectangularity andsubstantial roughness on their surface and sidewalls, and are hardlybelieved to clear the practically acceptable level. Of the problemsassociated with prior art resist materials, the most serious problem isthe unevenness of fine line size, which is generally referred to as“line edge roughness” (LER). Since the LER has a substantial impact onthe performance of semiconductor devices being fabricated, it isstrongly desired to overcome this problem. If it is merely required toform a pattern in a smooth finish, that purpose may be attained to amore or less extent by selecting a resin with a lower molecular weightand/or a photoacid generator which generates a more mobile acid. Withthis approach, however, not only properties such as exposure dosedependency, pattern density dependency, and mask fidelity are extremelyexacerbated, but also the line size itself rather becomes uneven becauseminute fluctuations at the mask are enlarged. This approach does notlead to a reduction of LER. Under the continuing demand for a furtherreduction of the pattern rule, the resist is required to provide goodperformance with respect to sensitivity, substrate adhesion and etchresistance and additionally, to find an essential solution to improveLER without sacrifice of resolution.

SUMMARY OF THE INVENTION

An object of the present invention is to provide lactone-containingcompounds useful as monomers for the synthesis of polymers, polymerscomprising recurring units derived from the lactone-containingcompounds, and resist compositions comprising the polymers, the resistcompositions exhibiting a high resolution and minimized pattern edgeroughness when processed by photolithography using high-energy radiationsuch as ArF excimer laser radiation as a light source. Another object isto provide a patterning process using the resist compositions.

The inventor has found that a lactone-containing compound of the generalformula (1) shown below can be readily prepared in high yields, and thata resist composition comprising a polymer derived from thelactone-containing compound as a base resin exhibits satisfactoryproperties including exposure dose dependency, pattern densitydependency, and mask fidelity as well as minimized pattern edgeroughness when processed by photolithography, so that the polymer isadvantageously used in resist form for precise micropatterning.

Accordingly, the present invention provides a lactone-containingcompound, polymer, resist composition, and patterning process, asdefined below.

-   [1] A lactone-containing compound having the general formula (1).

Herein R¹ is hydrogen, fluorine, methyl or trifluoromethyl, R² and R³are each independently a straight, branched or cyclic monovalenthydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bondtogether to form an aliphatic hydrocarbon ring with the carbon atom towhich they are attached, R⁴ is hydrogen or CO₂R⁵, R⁵ is a straight,branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atomswhich may have a halogen or oxygen atom, W is CH₂, O or S, with theproviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ whenW is O or S, and k¹ is 0 or 1.

-   [2] A polymer comprising recurring units derived from the    lactone-containing compound of [1].-   [3] A polymer comprising recurring units having the general formula    (2).

Herein R¹ to R⁴, W, and k¹ are as defined above.

-   [4] The polymer of [2] or [3], further comprising recurring units    having at least one of the general formulas (3) to (6):

wherein R¹ is as defined above, R⁶ and R⁷ are each independentlyhydrogen or hydroxyl, X is an acid labile group, Y is a substituentgroup having a lactone structure different from formula (1), and Z ishydrogen, a fluoroalkyl group of 1 to 15 carbon atoms or afluoroalcohol-containing substituent group of 1 to 15 carbon atoms.

-   [5] A resist composition comprising the polymer of any one of [2] to    [4] as a base resin.-   [6] A process for forming a pattern comprising the steps of applying    the resist composition of [5] onto a substrate to form a coating,    heat treating the coating, exposing the coating to high-energy    radiation or electron beam through a photomask, optionally heat    treating the exposed coating, and developing it with a developer.

It is noted that immersion lithography can be applied to the resistcomposition of the invention. The immersion lithography involvesprebaking a resist film and exposing the resist film to light through aprojection lens with a liquid medium interposed between the resist filmand the projection lens. The ArF immersion lithography uses deionizedwater as the immersion medium. This technology, combined with aprojection lens having a numerical aperture of at least 1.0, isimportant for the ArF lithography to survive to the 65 nm node, with afurther development thereof being accelerated.

The resist composition of the invention allows the feature size of thepattern after development to be reduced by various shrinkage techniques.For example, the hole size can be shrunk by such known techniques asthermal flow, RELACS, SAFIRE, and WASOOM. More effective shrinkage ofhole size by thermal flow is possible particularly when the inventivepolymer is blended with a hydrogenated cycloolefin ring-openingmetathesis polymer (ROMP) having a low Tg.

BENEFITS OF THE INVENTION

The lactone-containing compounds of the invention are useful as rawmaterials for the synthesis of functional materials, pharmaceutical andagricultural chemicals. They are most useful as monomers to producepolymers for the manufacture of radiation-sensitive resist compositionswhich have high transparency to radiation having a wavelength of up to500 nm, especially up to 300 nm, and exhibit good developmentproperties. Radiation-sensitive resist compositions comprising thepolymers as base resin exhibit high resolution and are improved inpattern edge roughness, pattern density dependency and exposure marginwhen processed by photolithography. The polymers are advantageously usedin resist form for precise micropatterning.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The singular forms “a,” “an” and “the” include plural referents unlessthe context clearly dictates otherwise.

The notation (Cn-Cm) means a group containing from n to m carbon atomsper group.

It is understood that for many structures represented by chemicalformulae, there can exist enantiomers and diastereomers. Unlessotherwise stated, a single formula collectively represents all suchstereoisomers. The stereoisomers may be used alone or in admixture.

Lactone-Containing Compound

The lactone-containing compounds of the invention have the generalformula (1).

Herein R¹ is a hydrogen atom, fluorine atom, methyl group ortrifluoromethyl group. R² and R³ are each independently a straight,branched or cyclic monovalent hydrocarbon group of 1 to 10 carbon atoms,or R² and R³ may bond together to form an aliphatic hydrocarbon ringwith the carbon atom to which they are attached. R⁴ is a hydrogen atomor CO₂R⁵ wherein R⁵ is a straight, branched or cyclic monovalenthydrocarbon group of 1 to 15 carbon atoms which may have one or morehalogen or oxygen atoms. W is CH₂, O or S, with the proviso that R⁴ isCO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ when W is O or S. Thesubscript k¹ is 0 or 1.

Examples of the straight, branched or cyclic monovalent C₁-C₁₀hydrocarbon group represented by R² and R³ include, but are not limitedto, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl,tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, and n-octyl. R² andR³ may be the same or different. The aliphatic hydrocarbon rings that R²and R³ together form with the carbon atom to which they are attached arepreferably those of 3 to 20 carbon atoms, more preferably 4 to 15 carbonatoms, and examples include cyclopropane, cyclobutane, cyclopentane,cyclohexane, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane,bicyclo[3.3.1]nonane, bicyclo[4.4.0]decane, and adamantane.

Examples of R⁵ include, but are not limited to, methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, cyclopentyl,cyclohexyl, 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-methylcyclohexyl,1-ethylcyclohexyl, 2-ethylhexyl, n-octyl,2-methyl-2-bicyclo[2.2.1]heptyl, 2-ethyl-2-bicyclo[2.2.1]heptyl,2-methyl-2-adamantyl, 2-ethyl-2-adamantyl,8-methyl-8-tricyclo[5.2.1.0^(2,6)]decyl,8-ethyl-8-tricyclo[5.2.1.0^(2,6)]decyl,3-methyl-3-tetracyclo[4.4.0.1^(2.5).1^(7,10)]dodecyl,3-ethyl-3-tetracyclo[4.4.0.1^(2.5).1^(7,10)]dodecyl, methoxymethyl,ethoxymethyl, methoxyethyl, ethoxyethyl, and methoxyethoxyethyl, as wellas the groups shown below.

It is noted that the broken line as depicted herein and throughout thespecification denotes a valence bond.

Illustrative examples of the compound having formula (1) are given belowwherein R¹ is as defined above.

The lactone-containing compounds of formula (1) can be produced by thereaction schemes A and B shown below, for example, but the invention isnot limited thereto.

Herein, R¹ to R⁴, W, and k¹ are as defined above. R⁸ is a hydrogen orhalogen atom. R⁹ is a halogen atom, hydroxyl group or —OR¹¹. R¹⁰ is ahalogen atom, hydroxyl group or —OR¹². R¹¹ is methyl, ethyl or a groupof the formula:

R¹² is methyl, ethyl or a group of the formula:

M^(a) is Li, Na, K, Mg_(1/2), Ca_(1/2) or a substituted or unsubstitutedammonium. M^(b) is Li, Na, K, MgY^(a) or ZnY^(a) wherein Y^(a) is ahalogen atom.

Preferably, the lactone-containing compounds of formula (1) wherein k¹is equal to 0 are produced by scheme A including steps (i) and (ii), andthe lactone-containing compounds of formula (1) wherein k¹ is equal to 1are produced by scheme B including steps (iii) to (v), although theinvention is not limited thereto.

More particularly, scheme A includes step (i) which is a reaction of ahydroxylactone compound (7) with an esterifying agent (8) into a(halo)acetic ester (9).

Notably, the synthesis of hydroxylactone compound (7) is described inJP-A 2000-159758 and U.S. Ser. No. 11/649,251 (Japanese PatentApplication No. 2006-001102). For example, hydroxylactone compound (7)wherein R⁴ is CO₂R can be synthesized according to the followingformula.

The reaction may be readily conducted by a well-known technique. Thepreferred esterifying agent (8) is an acid chloride (corresponding toformula (8) wherein R⁹ is chlorine) or a carboxylic acid (correspondingto formula (8) wherein R⁹ is hydroxyl). When an acid chloride is used asthe esterifying agent, the reaction may be conducted in a solventlesssystem or in a solvent such as methylene chloride, toluene, hexane,diethyl ether, tetrahydrofuran or acetonitrile, by sequentially orsimultaneously adding hydroxylactone compound (7), a corresponding acidchloride such as 2-chloroacetic acid chloride or 2-bromoacetic acidchloride, and a base such as triethylamine, pyridine or4-dimethylaminopyridine, and optionally cooling or heating. When acarboxylic acid is used as the esterifying agent, the reaction may beconducted in a solvent such as toluene or hexane, by heatinghydroxylactone compound (7) and a corresponding carboxylic acid such as2-chloroacetic acid or 2-bromoacetic acid, in the presence of an acidcatalyst, and optionally removing the water formed during reaction fromthe system. Examples of the acid catalyst used herein include mineralacids such as hydrochloric acid, sulfuric acid, nitric acid andperchloric acid, and organic acids such as p-toluenesulfonic acid andbenzenesulfonic acid.

Step (ii) is a reaction of a haloacetic ester (9) (formula (9) whereinR⁸ is a halogen atom) with a carboxylate salt (10) into alactone-containing compound (1).

The reaction may be conducted by a standard technique. The carboxylicacid salt (10) used herein may be any of commercially availablecarboxylic acid salts such as metal salts of carboxylic acids, or may beprepared in a reaction system using a corresponding carboxylic acid suchas methacrylic acid or acrylic acid and a base. The amount of carboxylicacid salt (10) used is preferably 0.5 to 10 moles, and more preferably1.0 to 3.0 moles per mole of the reactant, (halo)acetic ester (9). Withless than 0.5 mole of the carboxylic acid salt, a large proportion ofthe reactant may be left unreacted, leading to a substantial drop ofyield. Using more than 10 moles of the carboxylic acid salt may beuneconomical because of an increased cost of the salt and decreased potyields. When the carboxylic acid salt is prepared in a reaction systemusing a corresponding carboxylic acid and a base, the base used hereinmay be selected from among amines such as ammonia, triethylamine,pyridine, lutidine, collidine, and N,N-dimethylaniline; hydroxides suchas sodium hydroxide, potassium hydroxide, and tetramethylammoniumhydroxide; carbonates such as potassium carbonate and sodium hydrogencarbonate; metals such as sodium; metal hydrides such as sodium hydride;metal alkoxides such as sodium methoxide and potassium t-butoxide;organometallic compounds such as butyllithium and ethylmagnesiumbromide; and metal amides such as lithium diisopropylamide, and mixturesthereof. The amount of the base used is preferably 0.2 to 10 moles, andmore preferably 0.5 to 2.0 moles per mole of the carboxylic acid. Withless than 0.2 mole of the base, a large proportion of the carboxylicacid may run to waste, leading to a cost deficiency. With more than 10moles of the base, substantial side reactions may occur, resulting in asubstantial drop of yield.

A solvent may be used in the reaction of step (ii). Suitable solventsinclude hydrocarbons such as toluene, xylene, hexane and heptane;chlorinated solvents such as methylene chloride, chloroform anddichloroethane; ethers such as diethyl ether, tetrahydrofuran anddibutyl ether; ketones such as acetone and 2-butanone; esters such asethyl acetate and butyl acetate; nitrites such as acetonitrile; alcoholssuch as methanol and ethanol; aprotic polar solvents such asN,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide;and water, which may be used alone or in admixture. To the reactionsystem, a phase transfer catalyst such as tetrabutylammonium hydrogensulfate may be added. An appropriate amount of the phase transfercatalyst added is 0.0001 to 1.0 mole, and more preferably 0.001 to 0.5mole per mole of the reactant, (halo)acetic ester. Less than 0.0001 moleof the catalyst may exert little or no addition effect whereas more than1.0 mole may be uneconomical because of an increased expense.

For the esterification reaction described above, the reactiontemperature may be selected as appropriate in accordance with otherreaction conditions and is preferably in the range from −70° C. toapproximately the boiling point of the solvent, and more preferably inthe range from 0° C. to approximately the boiling point of the solvent.The higher the reaction temperature, the more outstanding become sidereactions. It is then important in attaining high yields that thereaction be carried out at as low a temperature as possible in the rangefor the reaction to proceed at a practically acceptable rate. Preferablythe reaction time is determined so as to attain increased yields bymonitoring the reaction process by thin-layer chromatography (TLC) orgas chromatography (GC). Usually, the reaction time is about 30 minutesto about 40 hours. From the reaction mixture, the lactone-containingcompound (1) is recovered through an ordinary aqueous workup. Ifnecessary, the compound may be purified by a standard technique such asdistillation, recrystallization or chromatography.

Referring to scheme B, steps (iii) and (iv) are conversion of(halo)acetic ester (9) with the aid of a base into a metal enolate (11),and nucleophilic addition reaction of the enolate with a carbonylcompound (12) to form a β-hydroxyester compound (13).

Examples of the base which can be used in conjunction with the aceticester of formula (9) wherein R⁸ is hydrogen include metal amides such assodium amide, potassium amide, lithium diisopropylamide, potassiumdiisopropylamide, lithium dicyclohexylamide, potassiumdicyclohexylamide, lithium 2,2,6,6-tetramethylpiperidine, lithiumbistrimethylsilylamide, sodium bistrimethylsilylamide, potassiumbistrimethylsilylamide, lithium isopropylcyclohexylamide, andbromo-magnesium diisopropylamide; alkoxides such as sodium methoxide,sodium ethoxide, lithium methoxide, lithium ethoxide, lithiumtert-butoxide, and potassium tert-butoxide; inorganic hydroxides such assodium hydroxide, lithium hydroxide, potassium hydroxide, bariumhydroxide, and tetra-n-butylammonium hydroxide; inorganic carbonatessuch as sodium carbonate, sodium hydrogen carbonate, lithium carbonate,and potassium carbonate; metal hydrides such as borane, alkylboranes,sodium hydride, lithium hydride, potassium hydride, and calcium hydride;and alkyl metal compounds such as trityllithium, tritylsodium,tritylpotassium, methyllithium, phenyllithium, sec-butyllithium,tert-butyllithium, and ethylmagnesium bromide. Examples of the basewhich can be used in conjunction with the haloacetic ester of formula(9) wherein R⁸ is halogen include, but are not limited to, metals suchas lithium, sodium, potassium, magnesium, and zinc (e.g., a reactionusing haloacetic ester and zinc is known as Reformatsky reaction).

In the addition reaction of metal enolate (11) with carbonyl compound(12), it is preferable to use 0.8 to 1.5 moles of the metal enolate permole of the carbonyl compound. Examples of the solvent used hereininclude ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether,1,4-dioxane, ethylene glycol dimethyl ether, and ethylene glycol diethylether, and hydrocarbons such as hexane, heptane, benzene, toluene,xylene, and cumene, which may be used alone or in admixture. Thereaction temperature and time vary with the identity of reactants used.For example, where a metal enolate is formed using as the reactants anacetic ester of formula (9) wherein R⁸ is hydrogen and a strong basesuch as lithium diisopropylamide or lithium bistrimethylsilylamide, theresulting metal enolate is thermally unstable, and it is then preferredthat the reaction temperature of step (iv) be kept as low as −80° C. to−30° C. and the reaction time be about 0.5 to 3 hours. In anotherexample where a metal enolate is formed using a haloacetic ester offormula (9) wherein R⁸ is halogen and a metal such as zinc or magnesium,it is preferred that the reaction temperature of step (iv) be kept at20° C. to 80° C. and the reaction time be about 1 to 20 hours. However,the reaction conditions are not limited thereto.

Step (v) is a reaction of the β-hydroxyester compound (13) with anesterifying agent (14) into a lactone-containing compound (1).

The reaction may be readily conducted by a well-known technique. Thepreferred esterifying agent (14) is an acid chloride (corresponding toformula (14) wherein R¹⁰ is chlorine) or a carboxylic acid(corresponding to formula (14) wherein R¹⁰ is hydroxyl). When an acidchloride is used as the esterifying agent, the reaction may be conductedin a solventless system or in a solvent such as methylene chloride,toluene or hexane, by sequentially or simultaneously adding β-hydroxylester compound (13), a corresponding acid chloride such as methacrylicacid chloride or acrylic acid chloride, and a base such astriethylamine, pyridine or 4-dimethylaminopyridine, and optionallycooling or heating. When a carboxylic acid is used as the esterifyingagent, the reaction may be conducted in a solvent such as toluene orhexane, by heating β-hydroxy ester compound (13) and a correspondingcarboxylic acid such as methacrylic acid or acrylic acid, in thepresence of an acid catalyst, and optionally removing the water formedduring reaction from the system. Examples of the acid catalyst usedherein include mineral acids such as hydrochloric acid, sulfuric acid,nitric acid and perchloric acid, and organic acids such asp-toluenesulfonic acid and benzenesulfonic acid.

Polymer

In the second aspect, the invention provides a polymer comprisingrecurring units derived from the lactone-containing compound of formula(1).

Specifically, the recurring units derived from the lactone-containingcompound of formula (1) include recurring units having the generalformula (2).

Herein R¹ to R⁴, W and k¹ are as defined above.

In addition to the recurring units derived from the compounds havingformula (1), specifically recurring units having formula (2), thepolymers of the invention may further comprise recurring units having atleast one of the general formulas (3) to (6).

Herein R¹ is as defined above, R⁶ and R⁷ are each independently ahydrogen atom or hydroxyl group, X is an acid labile group, Y is asubstituent group having a lactone structure different from formula (1),and Z is a hydrogen atom, a fluoroalkyl group of 1 to 15 carbon atoms ora fluoroalcohol-containing substituent group of 1 to 15 carbon atoms.

Under the action of acid, a polymer comprising recurring units offormula (3) is decomposed to generate carboxylic acid, turning to be analkali soluble polymer. The acid labile group represented by X may beselected from a variety of such groups. Examples of the acid labilegroup are groups of the following general formulae (L1) to (L4),tertiary alkyl groups of 4 to 20 carbon atoms, preferably 4 to 15 carbonatoms, trialkylsilyl groups in which each alkyl moiety has 1 to 6 carbonatoms, and oxoalkyl groups of 4 to 20 carbon atoms.

In these formulae, the broken line denotes a valence bond. R^(L01) andR^(L02) are hydrogen or straight, branched or cyclic alkyl groups of 1to 18 carbon atoms, preferably 1 to 10 carbon atoms. Exemplary alkylgroups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl, norbornyl,tricyclodecanyl, tetracyclododecanyl, and adamantyl. R^(L03) is amonovalent hydrocarbon group of 1 to 18 carbon atoms, preferably 1 to 10carbon atoms, which may contain a hetero atom such as oxygen, examplesof which include unsubstituted straight, branched or cyclic alkyl groupsand substituted forms of such alkyl groups in which some hydrogen atomsare replaced by hydroxyl, alkoxy, oxo, amino, alkylamino or the like.Illustrative examples of the substituted alkyl groups are shown below.

A pair of R^(L01) and R^(L02), R^(L01) and R^(L03), or R^(L02) andR^(L03) may form a ring with carbon and oxygen atoms to which they areattached. Each of R^(L01), R^(L02) and R^(L03) is a straight or branchedalkylene group of 1 to 18 carbon atoms, preferably 1 to 10 carbon atomswhen they form a ring.

R^(L04) is a tertiary alkyl group of 4 to 20 carbon atoms, preferably 4to 15 carbon atoms, a trialkylsilyl group in which each alkyl moiety has1 to 6 carbon atoms, an oxoalkyl group of 4 to 20 carbon atoms, or agroup of formula (L1). Exemplary tertiary alkyl groups are tert-butyl,tert-amyl, 1,1-diethylpropyl, 2-cyclopentylpropan-2-yl,2-cyclohexylpropan-2-yl, 2-(bicyclo[2.2.1]heptan-2-yl)propan-2-yl,2-(adamantan-1-yl)propan-2-yl, 1-ethylcyclopentyl, 1-butylcyclopentyl,1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl,1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, and 2-ethyl-2-adamantyl.Exemplary trialkylsilyl groups are trimethylsilyl, triethylsilyl, anddimethyl-tert-butylsilyl. Exemplary oxoalkyl groups are 3-oxocyclohexyl,4-methyl-2-oxooxan-4-yl, and 5-methyl-2-oxooxolan-5-yl. Letter y is aninteger of 0 to 6.

In formula (L3), R^(L05) is a substituted or unsubstituted, straight,branched or cyclic alkyl group of 1 to 8 carbon atoms or a substitutedor unsubstituted aryl group of 6 to 20 carbon atoms. Examples of theoptionally substituted alkyl group include straight, branched or cyclicalkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl,sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl, andcyclohexyl, and substituted forms of such groups in which some hydrogenatoms are substituted with hydroxyl, alkoxy, carboxy, alkoxycarbonyl,oxo, amino, alkylamino, cyano, mercapto, alkylthio, sulfo or othergroups. Examples of the optionally substituted aryl groups includephenyl, methylphenyl, naphthyl, anthryl, phenanthryl, and pyrenyl.Letter m is equal to 0 or 1, n is equal to 0, 1, 2 or 3, and 2m+n isequal to 2 or 3.

In formula (L4), R^(L06) is a substituted or unsubstituted, straight,branched or cyclic alkyl group of 1 to 8 carbon atoms or a substitutedor unsubstituted aryl group of 6 to 20 carbon atoms. Examples of thesegroups are the same as exemplified for R^(L05). R^(L07) to R^(L16)independently represent hydrogen or monovalent hydrocarbon groups of 1to 15 carbon atoms. Exemplary hydrocarbon groups are straight, branchedor cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, n-octyl,n-nonyl, n-decyl, cyclopentyl, cyclohexyl, cyclopentylmethyl,cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyland cyclohexylbutyl, and substituted forms of these groups in which somehydrogen atoms are replaced by hydroxyl, alkoxy, carboxy,alkoxycarbonyl, oxo, amino, alkylamino, cyano, mercapto, alkylthio,sulfo or other groups. Alternatively, R^(L07) to R^(L16), takentogether, form a ring (for example, a pair of R^(L07) and R^(L08),R^(L07) and R^(L09), R^(L08) and R^(L10), R^(L09) and R^(L10), R^(L11)and R^(L12), R^(L13) and R^(L14), or a similar pair form a ring). Eachof R^(L07) to R^(L16) represents a divalent C₁-C₁₅ hydrocarbon groupwhen they form a ring, examples of which are the ones exemplified abovefor the monovalent hydrocarbon groups, with one hydrogen atom beingeliminated. Two of R^(L07) to R^(L16) which are attached to vicinalcarbon atoms (for example, a pair of R^(L07) and R^(L09) R^(L09) andR^(L15), R^(L13) and R^(L15), or a similar pair) may bond togetherdirectly to form a double bond.

Of the acid labile groups of formula (L1), the straight and branchedones are exemplified by the following groups.

Of the acid labile groups of formula (L1), the cyclic ones are, forexample, tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl,tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl.

Examples of the acid labile groups of formula (L2) includetert-butoxycarbonyl, tert-butoxycarbonylmethyl, tert-amyloxycarbonyl,tert-amyloxycarbonylmethyl, 1,1-diethylpropyloxycarbonyl,1,1-diethylpropyloxycarbonylmethyl, 1-ethylcyclopentyloxycarbonyl,1-ethylcyclopentyloxycarbonylmethyl, 1-ethyl-2-cyclopentenyloxycarbonyl,1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl,2-tetrahydropyranyloxycarbonylmethyl, and2-tetrahydrofuranyloxycarbonylmethyl groups.

Examples of the acid labile groups of formula (L3) include1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl,1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl,1-cyclohexylcyclopentyl, 1-(4-methoxy-n-butyl)cyclopentyl,1-methylcyclohexyl, 1-ethylcyclohexyl, 3-methyl-1-cyclopenten-3-yl,3-ethyl-1-cyclopenten-3-yl, 3-methyl-1-cyclohexen-3-yl, and3-ethyl-1-cyclohexen-3-yl groups.

Of the acid labile groups having formula (L4), groups having thefollowing formulas (L4-1) to (L4-4) are preferred.

In formulas (L4-1) to (L4-4), the broken line denotes a bonding site anddirection. R^(L41) is each independently a monovalent hydrocarbon group,typically a straight, branched or cyclic alkyl group of 1 to 10 carbonatoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl and cyclohexyl.

For formulas (L4-1) to (L4-4), there can exist enantiomers anddiastereomers. Each of formulae (L4-1) to (L4-4) collectively representsall such stereoisomers. Such stereoisomers may be used alone or inadmixture.

For example, the general formula (L4-3) represents one or a mixture oftwo selected from groups having the following general formulas (L4-3-1)and (L4-3-2).

Similarly, the general formula (L4-4) represents one or a mixture of twoor more selected from groups having the following general formulas(L4-4-1) to (L4-4-4).

Each of formulas (L4-1) to (L4-4), (L4-3-1) and (L4-3-2), and (L4-4-1)to (L4-4-4) collectively represents an enantiomer thereof and a mixtureof enantiomers.

It is noted that in the above formulas (L4-1) to (L4-4), (L4-3-1) and(L4-3-2), and (L4-4-1) to (L4-4-4), the bond direction is on the exoside relative to the bicyclo[2.2.1]heptane ring, which ensures highreactivity for acid catalyzed elimination reaction (see JP-A2000-336121). In preparing these monomers having a tertiary exo-alkylgroup of bicyclo[2.2.1]heptane skeleton as a substituent group, theremay be contained monomers substituted with an endo-alkyl group asrepresented by the following formulas (L4-1-endo) to (L4-4-endo). Forgood reactivity, an exo proportion of at least 50% is preferred, with anexo proportion of at least 80% being more preferred.

See JP-A 2000-336121.

Illustrative examples of the acid labile group of formula (L4) are givenbelow.

Examples of the tertiary alkyl groups of 4 to 20 carbon atoms,trialkylsilyl groups in which each alkyl moiety has 1 to 6 carbon atoms,and oxoalkyl groups of 4 to 20 carbon atoms are as exemplified forR^(L04).

Illustrative examples of the recurring units of formula (3) are givenbelow although the invention is not limited thereto.

Illustrative examples of the recurring units of formula (4) are givenbelow although the invention is not limited thereto.

Illustrative examples of the recurring units of formula (5) are givenbelow although the invention is not limited thereto.

Illustrative examples of the recurring units of formula (6) are givenbelow although the invention is not limited thereto.

In addition to the foregoing units, the polymers of the invention mayfurther comprise recurring units derived from carbon-to-carbon doublebond-bearing monomers other than the above-described ones, for example,substituted acrylic acid esters such as methyl methacrylate, methylchrotonate, dimethyl maleate and dimethyl itaconate, unsaturatedcarboxylic acids such as maleic acid, fumaric acid, and itaconic acid,cyclic olefins such as norbornene, norbornene derivatives, andtetracyclo[4.4.0.1^(2,5).17^(7,10)]dodecene derivatives, unsaturatedacid anhydrides such as itaconic anhydride, and other monomers.

The polymers of the invention generally have a weight average molecularweight (Mw) of 1,000 to 500,000, and preferably 3,000 to 100,000, asmeasured by gel permeation chromatography (GPC) using polystyrenestandards. Outside the range, there may result an extreme drop of etchresistance, and a drop of resolution due to difficulty to gain adissolution rate difference before and after exposure.

In the inventive polymers, appropriate proportions of the respectiverecurring units derived from the monomers are given below although theinvention is not limited thereto. The inventive polymers may contain:

-   (I) constituent units of one or more types having formula (2)    derived from monomers of formula (1) in a proportion of more than 0    mol % to 100 mol %, preferably 5 to 70 mol %, and more preferably 10    to 50 mol %,-   (II) constituent units of one or more types having formulas (3)    to (6) in a proportion of 0 mol % to less than 100 mol %, preferably    1 to 95 mol %, and more preferably 20 to 90 mol %, and-   (III) constituent units of one or more types derived from other    monomers in a proportion of 0 to 80 mol %, preferably 0 to 70 mol %,    and more preferably 0 to 50 mol %, based on the total moles of    constituent units.

The polymers of the invention are prepared by copolymerization reactionusing the compound of formula (1) as a first monomer and polymerizabledouble bond-bearing compounds as second and subsequent monomers. Thecopolymerization reaction to produce the inventive polymers may beperformed in various modes, preferably radical polymerization, anionicpolymerization or coordination polymerization.

For radical polymerization, preferred reaction conditions include (a) asolvent selected from among hydrocarbons such as benzene, ethers such astetrahydrofuran, alcohols such as ethanol, and ketones such as methylisobutyl ketone, (b) a polymerization initiator selected from azocompounds such as 2,2′-azobisisobutyronitrile and peroxides such asbenzoyl peroxide and lauroyl peroxide, (c) a temperature of about 0° C.to about 100° C., and (d) a time of about ½ hour to about 48 hours.Reaction conditions outside the described range may be employed ifdesired.

For anionic polymerization, preferred reaction conditions include (a) asolvent selected from among hydrocarbons such as benzene, ethers such astetrahydrofuran, and liquid ammonia, (b) a polymerization initiatorselected from metals such as sodium and potassium, alkyl metals such asn-butyllithium and sec-butyllithium, ketyl, and Grignard reagents, (c) atemperature of about −78° C. to about 0° C., (d) a time of about ½ hourto about 48 hours, and (e) a stopper selected from among proton-donativecompounds such as methanol, halides such as methyl iodide, andelectrophilic compounds. Reaction conditions outside the described rangemay be employed if desired.

For coordination polymerization, preferred reaction conditions include(a) a solvent selected from among hydrocarbons such as n-heptane andtoluene, (b) a catalyst selected from Ziegler-Natta catalysts comprisinga transition metal (e.g., titanium) and alkylaluminum, Phillipscatalysts of metal oxides having chromium or nickel compounds carriedthereon, and olefin-metathesis mixed catalysts as typified by tungstenand rhenium mixed catalysts, (c) a temperature of about 0° C. to about100° C., and (d) a time of about ½ hour to about 48 hours. Reactionconditions outside the described range may be employed if desired.

Resist Composition

Since the polymer of the invention is useful as the base resin of aresist composition, the other aspect of the invention provides a resistcomposition comprising the polymer and specifically a chemicallyamplified positive resist composition comprising the polymer. Typically,the resist composition contains (A) the inventive polymer as a baseresin, (B) an acid generator, (C) an organic solvent, and optionally (D)a quencher and (E) a surfactant.

In addition to the inventive polymer, the base resin (A) may includeanother polymer having a dissolution rate in alkaline developer thatincreases under the action of acid, if necessary. Examples of the otherpolymer include, but are not limited to, (i) poly(meth)acrylic acidderivatives, (ii) norbornene derivative-maleic anhydride copolymers,(iii) hydrogenated products of ring-opening metathesis polymers (ROMP),and (iv) vinyl ether-maleic anhydride-(meth)acrylic acid derivativecopolymers.

Of these, the hydrogenated products of ring-opening metathesis polymersare synthesized by the method illustrated in JP-A 2003-66612.Illustrative examples of such hydrogenated polymers include thosepolymers having the recurring units shown below, but are not limitedthereto.

The inventive polymer and the other polymer are preferably blended in aweight ratio from 100:0 to 10:90, more preferably from 100:0 to 20:80.If the blend ratio of the inventive polymer is below this range, theresist composition would become poor in some of the desired properties.The properties of the resist composition can be adjusted by properlychanging the blend ratio of the inventive polymer.

The other polymer is not limited to one type and a mixture of two ormore other polymers may be added. The use of plural polymers allows foreasy adjustment of resist properties.

Photoacid Generator

As the acid generator (B), a photoacid generator is typically used. Itis any compound capable of generating an acid upon exposure tohigh-energy radiation. Suitable photoacid generators include sulfoniumsalts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, andoxime-O-sulfonate acid generators. Exemplary acid generators are givenbelow while they may be used alone or in admixture of two or more.

Sulfonium salts are salts of sulfonium cations with sulfonates,bis(substituted alkylsulfonyl)imides and tris(substitutedalkylsulfonyl)methides. Exemplary sulfonium cations includetriphenylsulfonium, (4-tert-butoxyphenyl)diphenylsulfonium,bis(4-tert-butoxyphenyl)phenylsulfonium,tris(4-tert-butoxyphenyl)sulfonium,(3-tert-butoxyphenyl)diphenylsulfonium,bis(3-tert-butoxyphenyl)phenylsulfonium,tris(3-tert-butoxyphenyl)sulfonium,(3,4-di-tert-butoxyphenyl)diphenylsulfonium,bis(3,4-di-tert-butoxyphenyl)phenylsulfonium,tris(3,4-di-tert-butoxyphenyl)sulfonium,diphenyl(4-thiophenoxyphenyl)sulfonium,(4-tert-butoxycarbonylmethyloxyphenyl)diphenylsulfonium,tris(4-tert-butoxycarbonylmethyloxyphenyl)sulfonium,(4-tert-butoxyphenyl)bis(4-dimethylaminophenyl)sulfonium,tris(4-dimethylaminophenyl)sulfonium, 4-methylphenyldiphenylsulfonium,4-tert-butylphenyldiphenylsulfonium, bis(4-methylphenyl)phenylsulfonium,bis(4-tert-butylphenyl)phenylsulfonium, tris(4-methylphenyl)sulfonium,tris(4-tert-butylphenyl)sulfonium, tris(phenylmethyl)sulfonium,2-naphthyldiphenylsulfonium, dimethyl(2-naphthyl)sulfonium,4-hydroxyphenyldimethylsulfonium, 4-methoxyphenyldimethylsulfonium,trimethylsulfonium, 2-oxocyclohexylcyclohexylmethylsulfonium,trinaphthylsulfonium, tribenzylsulfonium, diphenylmethylsulfonium,dimethylphenylsulfonium, 2-oxopropylthiacyclopentanium,2-oxobutylthiacyclopentanium, 2-oxo-3,3-dimethylbutylthiacyclopentanium,2-oxo-2-phenylethylthiacyclopentanium,4-n-butoxynaphthyl-1-thiacyclopentanium, and2-n-butoxynaphthyl-1-thiacyclopentanium. Exemplary sulfonates includetrifluoromethanesulfonate, pentafluoroethanesulfonate,heptafluoropropanesulfonate, nonafluorobutanesulfonate,tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate,heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate,pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate,4-fluorobenzenesulfonate, mesitylenesulfonate,2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate,4-(p-toluenesulfonyloxy)benzenesulfonate,6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate,4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, methanesulfonate,1,1-difluoro-2-naphthyl-ethanesulfonate,1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate,2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yloxy-carbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate. Exemplarybis(substituted alkylsulfonyl)imides includebis(trifluoromethylsulfonyl)imide, bis(pentafluoroethylsulfonyl)imide,bis(heptafluoropropylsulfonyl)imide, andperfluoro(1,3-propylenebissulfonyl)imide. A typical tris(substitutedalkylsulfonyl)methide is tris(trifluoromethylsulfonyl)methide. Sulfoniumsalts based on combination of the foregoing-examples are included.

Iodonium salts are salts of iodonium cations with sulfonates,bis(substituted alkylsulfonyl)imides and tris(substitutedalkylsulfonyl)methides. Exemplary iodonium cations are aryliodoniumcations including diphenyliodinium, bis(4-tert-butylphenyl)iodonium,4-tert-butoxyphenylphenyliodonium, and 4-methoxyphenylphenyliodonium.Exemplary sulfonates include trifluoromethanesulfonate,pentafluoroethanesulfonate, heptafluoropropanesulfonate,nonafluorobutanesulfonate, tridecafluorohexanesulfonate,perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate,2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate,4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate,mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate,toluenesulfonate, benzenesulfonate,4-(p-toluenesulfonyloxy)benzenesulfonate,6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate,4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, methanesulfonate,1,1-difluoro-2-naphthyl-ethanesulfonate,1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate,2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yloxy-carbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate. Exemplarybis(substituted alkylsulfonyl)imides includebis(trifluoromethylsulfonyl)imide, bis(pentafluoroethylsulfonyl)imide,bis(heptafluoropropylsulfonyl)imide, andperfluoro(1,3-propylenebissulfonyl)imide. A typical tris(substitutedalkylsulfonyl)methide is tris(trifluoromethylsulfonyl)methide. Iodoniumsalts based on combination of the foregoing examples are included.

Exemplary sulfonyldiazomethane compounds include bissulfonyldiazomethanecompounds and sulfonyl-carbonyldiazomethane compounds such asbis(ethylsulfonyl)diazomethane, bis(1-methylpropylsulfonyl)diazomethane,bis(2-methylpropylsulfonyl)diazomethane,bis(1,1-dimethylethylsulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane,bis(perfluoroisopropylsulfonyl)diazomethane,bis(phenylsulfonyl)diazomethane,bis(4-methylphenylsulfonyl)diazomethane,bis(2,4-dimethylphenylsulfonyl)diazomethane,bis(4-acetyloxyphenylsulfonyl)diazomethane,bis(4-(methanesulfonyloxy)phenylsulfonyl)diazomethane,bis(4-(p-toluenesulfonyloxy)phenylsulfonyl)diazomethane,bis(4-n-hexyloxyphenylsulfonyl)diazomethane,bis(2-methyl-4-n-hexyloxyphenylsulfonyl)diazomethane,bis(2,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane,bis(3,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane,bis(2-methyl-5-isopropyl-4-n-hexyloxyphenylsulfonyl)-diazomethane,bis(2-naphthylsulfonyl)diazomethane,4-methylphenylsulfonylbenzoyldiazomethane,tert-butylcarbonyl-4-methylphenylsulfonyldiazomethane,2-naphthylsulfonylbenzoyldiazomethane,4-methylphenylsulfonyl-2-naphthoyldiazomethane,methylsulfonylbenzoyldiazomethane, andtert-butoxycarbonyl-4-methylphenylsulfonyldiazomethane.

N-sulfonyloxydicarboxyimide photoacid generators include combinations ofimide skeletons with sulfonates. Exemplary imide skeletons aresuccinimide, naphthalenedicarboxyimide, phthalimide,cyclohexyldicarboxyimide, 5-norbornene-2,3-dicarboxyimide, and7-oxabicyclo[2.2.1]-5-heptene-2,3-dicarboxyimide. Exemplary sulfonatesinclude trifluoromethanesulfonate, pentafluoroethanesulfonate,heptafluoropropanesulfonate, nonafluorobutanesulfonate,tridecafluorohexanesulfonate, perfluoro(4-ethylcyclohexane)sulfonate,heptadecafluorooctanesulfonate, 2,2,2-trifluoroethanesulfonate,pentafluorobenzenesulfonate, 4-(trifluoromethyl)benzenesulfonate,4-fluorobenzenesulfonate, mesitylenesulfonate,2,4,6-triisopropylbenzenesulfonate, toluenesulfonate, benzenesulfonate,4-(p-toluenesulfonyloxy)benzenesulfonate,6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate,4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, methanesulfonate,1,1-difluoro-2-naphthyl-ethanesulfonate,1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate,2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Benzoinsulfonate photoacid generators include benzoin tosylate, benzoinmesylate, and benzoin butanesulfonate.

Pyrogallol trisulfonate photoacid generators include pyrogallol,phloroglucin, catechol, resorcinol, hydroquinone, in which all thehydroxyl groups are substituted by trifluoromethanesulfonate,pentafluoroethanesulfonate, heptafluoropropanesulfonate,nonafluorobutanesulfonate, tridecafluorohexanesulfonate,perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate,2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate,4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate,mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate,toluenesulfonate, benzenesulfonate,4-(p-toluenesulfonyloxy)benzenesulfonate,6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate,4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, methanesulfonate,1,1-difluoro-2-naphthylethanesulfonate,1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate,2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate, etc.

Nitrobenzyl sulfonate photoacid generators include 2,4-dinitrobenzylsulfonate, 2-nitrobenzyl sulfonate, and 2,6-dinitrobenzyl sulfonate,with exemplary sulfonates including trifluoromethanesulfonate,pentafluoroethanesulfonate, heptafluoropropanesulfonate,nonafluorobutanesulfonate, tridecafluorohexanesulfonate,perfluoro(4-ethylcyclohexane)sulfonate, heptadecafluorooctanesulfonate,2,2,2-trifluoroethanesulfonate, pentafluorobenzenesulfonate,4-(trifluoromethyl)benzenesulfonate, 4-fluorobenzenesulfonate,mesitylenesulfonate, 2,4,6-triisopropylbenzenesulfonate,toluenesulfonate, benzenesulfonate,4-(p-toluenesulfonyloxy)benzenesulfonate,6-(p-toluenesulfonyloxy)naphthalene-2-sulfonate,4-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,5-(p-toluenesulfonyloxy)naphthalene-1-sulfonate,8-(p-toluenesulfonyloxy)naphthalene-1-sulfonate, naphthalenesulfonate,camphorsulfonate, octanesulfonate, dodecylbenzenesulfonate,butanesulfonate, methanesulfonate,1,1-difluoro-2-naphthylethanesulfonate,1,1,2,2-tetrafluoro-2-(norbornan-2-yl)ethanesulfonate,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodec-3-en-8-yl)ethanesulfonate,2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate, etc. Also usefulare nitrobenzyl sulfonate analogues in which the nitro group on thebenzyl side is substituted by a trifluoromethyl group.

Sulfone photoacid generators include bis(phenylsulfonyl)methane,bis(4-methylphenylsulfonyl)methane, bis(2-naphthylsulfonyl)methane,2,2-bis(phenylsulfonyl)propane, 2,2-bis(4-methylphenylsulfonyl)propane,2,2-bis(2-naphthylsulfonyl)propane,2-methyl-2-(p-toluenesulfonyl)propiophenone,2-cyclohexylcarbonyl-2-(p-toluenesulfonyl)propane, and2,4-dimethyl-2-(p-toluenesulfonyl)pentan-3-one.

Suitable O-arylsulfonyloxime compounds and O-alkylsulfonyloximecompounds (oxime sulfonates) include photoacid generators in the form ofglyoxime derivatives; photoacid generators in the form of oximesulfonates with a long conjugated system separated by thiophene orcyclohexadiene; oxime sulfonates having an electron withdrawing groupsuch as trifluoromethyl incorporated for increased stability; oximesulfonates using phenylacetonitrile or substituted acetonitrilederivatives; and bisoxime sulfonates.

Photoacid generators in the form of glyoxime derivatives includebis-O-(p-toluenesulfonyl)-α-dimethylglyoxime,bis-O-(p-toluenesulfonyl)-α-diphenylglyoxime,bis-O-(p-toluenesulfonyl)-α-dicyclohexylglyoxime,bis-O-(p-toluenesulfonyl)-2,3-pentanedionedioxime,bis-O-(n-butanesulfonyl)-α-dimethylglyoxime,bis-O-(n-butanesulfonyl)-α-diphenylglyoxime,bis-O-(n-butanesulfonyl)-α-dicyclohexylglyoxime,bis-O-(methanesulfonyl)-α-dimethylglyoxime,bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime,bis-O-(2,2,2-trifluoroethanesulfonyl)-α-dimethylglyoxime,bis-O-(10-camphorsulfonyl)-α-dimethylglyoxime,bis-O-(benzenesulfonyl)-α-dimethylglyoxime,bis-O-(4-fluorobenzenesulfonyl)-α-dimethylglyoxime,bis-O-(4-trifluoromethylbenzenesulfonyl)-α-dimethylglyoxime,bis-O-(xylenesulfonyl)-α-dimethylglyoxime,bis-O-(trifluoromethanesulfonyl)-nioxime,bis-O-(2,2,2-trifluoroethanesulfonyl)-nioxime,bis-O-(10-camphorsulfonyl)-nioxime, bis-O-(benzenesulfonyl)-nioxime,bis-O-(4-fluorobenzenesulfonyl)-nioxime,bis-O-(4-(trifluoromethyl)benzenesulfonyl)-nioxime, andbis-O-(xylenesulfonyl)-nioxime. Also included are modified forms of theforegoing compounds having substituted on their skeleton2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Photoacid generators in the form of oxime sulfonates with a longconjugated system separated by thiophene or cyclohexadiene include(5-(p-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenyl-acetonitrile,(5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)phenyl-acetonitrile,(5-n-octanesulfonyloxyimino-5H-thiophen-2-ylidene)phenyl-acetonitrile,(5-(p-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,(5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,(5-n-octanesulfonyloxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,(5-(4-(p-toluenesulfonyloxy)benzenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenylacetonitrile,and(5-(2,5-bis(p-toluenesulfonyloxy)benzenesulfonyl)oxyimino-5H-thiophen-2-ylidene)phenylacetonitrile.Also included are modified forms of the foregoing compounds havingsubstituted on their skeleton2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropane-sulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethane-sulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Suitable oxime sulfonates having an electron withdrawing group such astrifluoromethyl incorporated for increased stability include2,2,2-trifluoro-1-phenyl-ethanone O-(methylsulfonyl)oxime,2,2,2-trifluoro-1-phenyl-ethanone O-(10-camphorsulfonyl)-oxime,2,2,2-trifluoro-1-phenylethanone O-(4-methoxybenzenesulfonyl)oxime,2,2,2-trifluoro-1-phenylethanone O-(1-naphthylsulfonyl)oxime,2,2,2-trifluoro-1-phenylethanone O-(2-naphthylsulfonyl)oxime,2,2,2-trifluoro-1-phenylethanone O-(2,4,6-trimethylphenylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methylphenyl)ethanone O-(10-camphorsulfonyl)oxime,2,2,2-trifluoro-1-(4-methylphenyl)ethanone O-(methylsulfonyl)oxime,2,2,2-trifluoro-1-(2-methylphenyl)ethanone O-(10-camphorsulfonyl)oxime,2,2,2-trifluoro-1-(2,4-dimethylphenyl)ethanoneO-(10-camphorsulfonyl)oxime,2,2,2-trifluoro-1-(2,4-dimethylphenyl)ethanoneO-(1-naphthylsulfonyl)oxime,2,2,2-trifluoro-1-(2,4-dimethylphenyl)-ethanoneO-(2-naphthylsulfonyl)oxime,2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)ethanoneO-(10-camphorsulfonyl)oxime,2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)ethanoneO-(1-naphthylsulfonyl)oxime,2,2,2-trifluoro-1-(2,4,6-trimethylphenyl)ethanoneO-(2-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanoneO-(methyl-sulfonyl)oxime,2,2,2-trifluoro-1-(4-methylthiophenyl)-ethanoneO-(methyl-sulfonyl)oxime,2,2,2-trifluoro-1-(3,4-dimethoxyphenyl)ethanoneO-(methyl-sulfonyl)oxime, 2,2,2-trifluoro-1-(4-methoxyphenyl)ethanoneO-(4-methylphenylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methoxyphenyl)ethanoneO-(4-methoxyphenylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methoxyphenyl)ethanoneO-(4-dodecylphenylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methoxyphenyl)ethanone O-(octylsulfonyl)oxime,2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanoneO-(4-methoxyphenylsulfonyl)oxime,2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanoneO-(4-dodecylphenylsulfonyl)oxime,2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanone O-(octylsulfonyl)oxime,2,2,2-trifluoro-1-(4-thiomethylphenyl)ethanoneO-(2-naphthylsulfonyl)oxime, 2,2,2-trifluoro-1-(2-methylphenyl)ethanoneO-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-methylphenyl)ethanoneO-(phenylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-chlorophenyl)ethanoneO-(phenylsulfonyl)oxime, 2,2,3,3,4,4,4-heptafluoro-1-phenylbutanoneO-(10-camphorsulfonyl)oxime, 2,2,2-trifluoro-1-(1-naphthyl)ethanoneO-(methylsulfonyl)-oxime, 2,2,2-trifluoro-1-(2-naphthyl)ethanoneO-(methylsulfonyl)-oxime, 2,2,2-trifluoro-1-(4-benzylphenyl)ethanoneO-(methylsulfonyl)oxime,2,2,2-trifluoro-1-(4-(phenyl-1,4-dioxa-but-1-yl)phenyl)-ethanoneO-(methylsulfonyl)oxime, 2,2,2-trifluoro-1-(1-naphthyl)ethanoneO-(propylsulfonyl)-oxime, 2,2,2-trifluoro-1-(2-naphthyl)ethanoneO-(propylsulfonyl)-oxime, 2,2,2-trifluoro-1-(4-benzylphenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methylsulfonylphenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methylsulfonyloxyphenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methylcarbonyloxyphenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(6H,7H-5,8-dioxonaphth-2-yl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methoxycarbonylmethoxyphenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(4-methoxycarbonyl)-(4-amino-1-oxa-pent-1-yl)phenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(3,5-dimethyl-4-ethoxyphenyl)ethanoneO-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(4-benzyloxyphenyl)ethanoneO-(propylsulfonyl)oxime, 2,2,2-trifluoro-1-(2-thiophenyl)ethanoneO-(propylsulfonate)-oxime, and2,2,2-trifluoro-1-(1-dioxathiophen-2-yl)ethanoneO-(propylsulfonate)oxime;2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(trifluoromethanesulfonyloxyimino)ethyl)phenoxy)propoxy)phenyl)ethanoneO-(trifluoromethanesulfonyl)oxime,2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(1-propanesulfonyloxyimino)ethyl)phenoxy)propoxy)phenyl)ethanoneO-(propylsulfonyl)oxime,2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(1-butanesulfonyloxyimino)ethyl)phenoxy)propoxy)phenyl)ethanone.O-(butylsulfonyl)oxime,2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(4-(4-methylphenylsulfonyloxy)phenylsulfonyloxyimino)ethyl)phenoxy)-propoxy)phenyl)ethanoneO-(4-(4-methylphenylsulfonyloxy)-phenylsulfonyl)oxime, and2,2,2-trifluoro-1-(4-(3-(4-(2,2,2-trifluoro-1-(2,5-bis(4-methylphenylsulfonyloxy)benzenesulfonyloxy)phenylsulfonyl-oxyimino)ethyl)phenoxy)propoxy)phenyl)ethanoneO-(2,5-bis(4-methylphenylsulfonyloxy)benzenesulfonyloxy)phenylsulfonyl)-oxime.

Also included are modified forms of the foregoing compounds havingsubstituted on their skeleton2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Also included are oxime sulfonates having the formula (Ox-1):

wherein R⁴⁰¹ is a substituted or unsubstituted C₁-C₁₀ haloalkylsulfonylor halobenzenesulfonyl group, R⁴⁰² is a C₁-C₁₁ haloalkyl group, andAr⁴⁰¹ is substituted or unsubstituted aromatic or hetero-aromatic group.

Examples include2-[2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)-pentyl]fluorene,2-[2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)-butyl]fluorene,2-[2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)-hexyl]fluorene,2-[2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)-pentyl]-4-biphenyl,2-[2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)-butyl]-4-biphenyl,and2-[2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)-hexyl]-4-biphenyl.

Also included are modified forms of the foregoing compounds havingsubstituted on their skeleton2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Suitable oxime sulfonate generators using substituted acetonitrilederivatives include α-(p-toluenesulfonyloxyimino)-phenylacetonitrile,α-(p-chlorobenzenesulfonyloxyimino)-phenylacetonitrile,α-(4-nitrobenzenesulfonyloxyimino)-phenylacetonitrile,α-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)-phenylacetonitrile,α-(benzenesulfonyloxyimino)-4-chlorophenylacetonitrile,α-(benzenesulfonyloxyimino)-2,4-dichlorophenylacetonitrile,α-(benzenesulfonyloxyimino)-2,6-dichlorophenylacetonitrile,α-(benzenesulfonyloxyimino)-4-methoxyphenylacetonitrile,α-(2-chlorobenzenesulfonyloxyimino)-4-methoxyphenylacetonitrile,α-(benzenesulfonyloxyimino)-2-thienylacetonitrile,α-(4-dodecylbenzenesulfonyloxyimino)-phenylacetonitrile,α-[(4-toluenesulfonyloxyimino)-4-methoxyphenyl]acetonitrile,α-[(dodecylbenzenesulfonyloxyimino)-4-methoxyphenyl]-acetonitrile,α-(tosyloxyimino)-3-thienylacetonitrile,α-(methylsulfonyloxyimino)-1-cyclopentenylacetonitrile,α-(ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile,α-(isopropylsulfonyloxyimino)-1-cyclopentenylacetonitrile,α-(n-butylsulfonyloxyimino)-1-cyclopentenylacetonitrile,α-(ethylsulfonyloxyimino)-1-cyclohexenylacetonitrile,α-(isopropylsulfonyloxyimino)-1-cyclohexenylacetonitrile, andα-(n-butylsulfonyloxyimino)-1-cyclohexenylacetonitrile. Also includedare modified forms of the foregoing compounds having substituted ontheir skeleton 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

Suitable bisoxime sulfonates includebis(α-(p-toluenesulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(benzenesulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(methanesulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(butanesulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(10-camphorsulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(trifluoromethanesulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(4-methoxybenzenesulfonyloxy)imino)-p-phenylenediacetonitrile,bis(α-(4-toluenesulfonyloxy)imino)-m-phenylenediacetonitrile,bis(α-(benzenesulfonyloxy)imino)-m-phenylenediacetonitrile,bis(α-(methanesulfonyloxy)imino)-m-phenylenediacetonitrile,bis(α-(butanesulfonyloxy)imino)-m-phenylenediacetonitrile,bis(α-(10-camphorsulfonyloxy)imino)-m-phenylenediacetonitrile,bis(α-(trifluoromethanesulfonyloxy)imino)-m-phenylenediacetonitrile,bis(α-(4-methoxybenzenesulfonyloxy)imino)-m-phenylenediacetonitrile,etc.

Also included are modified forms of the foregoing compounds havingsubstituted on their skeleton2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-(4-phenylbenzoyloxy)propanesulfonate,1,1,3,3,3-pentafluoro-2-pivaloyloxypropanesulfonate,2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-furoyloxypropanesulfonate,2-naphthoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-(4-tert-butylbenzoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,2-acetyloxy-1,1,3,3,3-pentafluoropropanesulfonate,1,1,3,3,3-pentafluoro-2-hydroxypropanesulfonate,1,1,3,3,3-pentafluoro-2-tosyloxypropanesulfonate,1,1-difluoro-2-tosyloxyethanesulfonate,adamantanemethoxycarbonyldifluoromethanesulfonate,1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,methoxycarbonyldifluoromethanesulfonate,1-(hexahydro-2-oxo-3,5-methano-2H-cyclopenta[b]furan-6-yl-oxycarbonyl)difluoromethanesulfonate,and 4-oxo-1-adamantyloxycarbonyldifluoromethanesulfonate.

When the photoacid generator (B) is added to the KrF excimer laserresist composition, preference is given to sulfonium salts,bissulfonyldiazomethanes, N-sulfonyloxyimides and oxime-O-sulfonates.Illustrative preferred photoacid generators include triphenylsulfoniump-toluenesulfonate, triphenylsulfonium camphorsulfonate,triphenylsulfonium pentafluorobenzenesulfonate, triphenylsulfoniumnonafluorobutanesulfonate, triphenylsulfonium4-(p-toluenesulfonyloxy)benzenesulfonate, triphenylsulfonium2,4,6-triisopropylbenzenesulfonate, 4-tert-butoxyphenyldiphenylsulfoniump-toluenesulfonate, 4-tert-butoxyphenyldiphenylsulfoniumcamphorsulfonate, 4-tert-butoxyphenyldiphenylsulfonium4-(p-toluenesulfonyloxy)benzenesulfonate,4-tert-butylphenyldiphenylsulfonium camphorsulfonate,tris(4-methylphenyl)sulfonium camphorsulfonate,tris(4-tert-butylphenyl)sulfonium camphorsulfonate,bis(tert-butylsulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane,bis(2,4-dimethylphenylsulfonyl)diazomethane,bis(4-n-hexyloxyphenylsulfonyl)diazomethane,bis(2-methyl-4-n-hexyloxyphenylsulfonyl)diazomethane,bis(2,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane,bis(3,5-dimethyl-4-n-hexyloxyphenylsulfonyl)diazomethane,bis(2-methyl-5-isopropyl-4-n-hexyloxy)phenylsulfonyldiazomethane,bis(4-tert-butylphenylsulfonyl)diazomethane,N-camphorsulfonyloxy-5-norbornene-2,3-dicarboxylic acid imide,N-p-toluenesulfonyloxy-5-norbornene-2,3-dicarboxylic acid imide,(5-(10-camphorsulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile,and(5-(p-toluenesulfonyl)oxyimino-5H-thiophen-2-ylidene)(2-methylphenyl)acetonitrile.

When the photoacid generator (B) is added to the ArF laser resistcomposition, preference is given to sulfonium salts andoxime-O-sulfonates. Illustrative preferred photoacid generators includetriphenylsulfonium trifluoromethanesulfonate, triphenylsulfoniumpentafluoroethanesulfonate, triphenylsulfoniumheptafluoropropanesulfonate, triphenylsulfoniumnonafluorobutanesulfonate, triphenylsulfoniumtridecafluorohexanesulfonate, triphenylsulfoniumheptadecafluorooctanesulfonate, triphenylsulfoniumperfluoro(4-ethylcyclohexane)sulfonate, 4-methylphenyldiphenylsulfoniumnonafluorobutanesulfonate, 2-oxo-2-phenylethylthiacyclopentaniumnonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfoniumnonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfoniumperfluoro(4-ethylcyclohexane)sulfonate,4-tert-butylphenyldiphenylsulfonium heptafluorooctanesulfonate,triphenylsulfonium 1,1-difluoro-2-naphthylethanesulfonate,triphenylsulfonium1,1,2,2-tetrafluoro-2-(norbornan-2-yl)-ethanesulfonate,triphenylsulfonium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium1,1,3,3,3-pentafluoro-2-(pivaloyloxy)-propanesulfonate,triphenylsulfonium2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium 2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium adamantanemethoxycarbonyldifluoromethanesulfonate,triphenylsulfonium1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,triphenylsulfonium methoxycarbonyldifluoromethanesulfonate,4-tert-butylphenyldiphenylsulfonium2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium1,1,3,3,3-pentafluoro-2-(pivaloyloxy)propanesulfonate,4-tert-butylphenyldiphenylsulfonium2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfoniumadamantanemethoxycarbonyldifluoromethanesulfonate,4-tert-butylphenyldiphenylsulfonium1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,4-tert-butylphenyldiphenylsulfoniummethoxycarbonyldifluoromethanesulfonate,2-oxo-2-phenylethylthiacyclopentanium2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-oxo-2-phenylethylthiacyclopentanium2-cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium perfluoro(1,3-propylenebissulfonyl)imide,triphenylsulfonium bis(pentafluoroethylsulfonyl)imide,2-(2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)pentyl)fluorene,2-(2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)butyl)fluorene,2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene,2-(2,2,3,3,4,4,5,5-octafluoro-1-(2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)pentyl)fluorene,2-(2,2,3,3,4,4-pentafluoro-1-(2-(cyclohexanecaronyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)butyl)fluorene,and2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene.

When the photoacid generator (B) is added to the ArF immersionlithography resist composition, preference is given to sulfonium saltsand oxime-O-sulfonates. Illustrative preferred photoacid generatorsinclude triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfoniumtridecafluorohexanesulfonate, triphenylsulfoniumheptadecafluorooctanesulfonate, triphenylsulfoniumperfluoro(4-ethylcyclohexane)sulfonate, 4-methylphenyldiphenylsulfoniumnonafluorobutanesulfonate, 2-oxo-2-phenylethylthiacyclopentaniumnonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfoniumnonafluorobutanesulfonate, 4-tert-butylphenyldiphenylsulfoniumperfluoro(4-ethylcyclohexane)sulfonate,4-tert-butylphenyldiphenylsulfonium heptafluorooctanesulfonate,triphenylsulfonium 1,1-difluoro-2-naphthylethanesulfonate,triphenylsulfonium1,1,2,2-tetrafluoro-2-(norbornan-2-yl)-ethanesulfonate,triphenylsulfonium 2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium1,1,3,3,3-pentafluoro-2-(pivaloyloxy)-propanesulfonate,triphenylsulfonium2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium 2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium adamantanemethoxycarbonyldifluoromethanesulfonate,triphenylsulfonium1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,triphenylsulfonium methoxycarbonyldifluoromethanesulfonate,4-tert-butylphenyldiphenylsulfonium2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium1,1,3,3,3-pentafluoro-2-(pivaloyloxy)propanesulfonate,4-tert-butylphenyldiphenylsulfonium2-(cyclohexanecarbonyl-oxy)-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium2-(2-naphthoyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium2-(1-adamantanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfonium2-hydroxy-1,1,3,3,3-pentafluoropropanesulfonate,4-tert-butylphenyldiphenylsulfoniumadamantanemethoxycarbonyldifluoromethanesulfonate,4-tert-butylphenyldiphenylsulfonium1-(3-hydroxymethyladamantane)methoxycarbonyldifluoromethanesulfonate,4-tert-butylphenyldiphenylsulfoniummethoxycarbonyldifluoromethanesulfonate,2-oxo-2-phenylethylthiacyclopentanium2-benzoyloxy-1,1,3,3,3-pentafluoropropanesulfonate,2-oxo-2-phenylethylthiacyclopentanium2-cyclohexanecarbonyloxy-1,1,3,3,3-pentafluoropropanesulfonate,triphenylsulfonium perfluoro(1,3-propylenebissulfonyl)imide,triphenylsulfonium bis(pentafluoroethylsulfonyl)imide,2-(2,2,3,3,4,4,5,5-octafluoro-1-(nonafluorobutylsulfonyloxyimino)pentyl)fluorene,2-(2,2,3,3,4,4-pentafluoro-1-(nonafluorobutylsulfonyloxyimino)butyl)fluorene,2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene,2-(2,2,3,3,4,4,5,5-octafluoro-1-(2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)pentyl)fluorene,2-(2,2,3,3,4,4-pentafluoro-1-(2-(cyclohexanecarbonyloxy)-1,1,3,3,3-pentafluoropropanesulfonyloxyimino)butyl)fluorene,and2-(2,2,3,3,4,4,5,5,6,6-decafluoro-1-(nonafluorobutylsulfonyloxyimino)hexyl)fluorene.

In the chemically amplified resist composition, the photoacid generator(B) may be added in any desired amount as long as the objects of theinvention are not compromised. An appropriate amount of the photoacidgenerator (B) is 0.1 to 10 parts, and more preferably 0.1 to 5 parts byweight per 100 parts by weight of the base resin in the composition. Toohigh a proportion of the photoacid generator (B) may give rise toproblems of degraded resolution and foreign matter upon development andresist film peeling. The photoacid generators may be used alone or inadmixture of two or more. The transmittance of the resist film can becontrolled by using an photoacid generator having a low transmittance atthe exposure wavelength and adjusting the amount of the photoacidgenerator added.

It is noted that an acid diffusion controlling function may be providedwhen two or more photoacid generators are used in admixture providedthat one photoacid generator is an onium salt capable of generating aweak acid. Specifically, in a system using a mixture of a photoacidgenerator capable of generating a strong acid (e.g., fluorinatedsulfonic acid) and an onium salt capable of generating a weak acid(e.g., non-fluorinated sulfonic acid or carboxylic acid), if the strongacid generated from the photoacid generator upon exposure to high-energyradiation collides with the unreacted onium salt having a weak acidanion, then a salt exchange occurs whereby the weak acid is released andan onium salt having a strong acid anion is formed. In this course, thestrong acid is exchanged into the weak acid having a low catalysis,incurring apparent deactivation of the acid for enabling to control aciddiffusion.

If an onium salt capable of generating a strong acid and an onium saltcapable of generating a weak acid are used in admixture, an exchangefrom the strong acid to the weak acid as above can take place, but itnever happens that the weak acid collides with the unreacted onium saltcapable of generating a strong acid to induce a salt exchange. This isbecause of a likelihood of an onium cation forming an ion pair with astronger acid anion.

In the resist composition of the invention, there may be added acompound which is decomposed with an acid to generate another acid, thatis, acid amplifier compound. For these compounds, reference should bemade to J. Photopolym. Sci. and Tech., 8, 43-44, 45-46 (1995), andibid., 9, 29-30 (1996).

Examples of the acid amplifier compound includetert-butyl-2-methyl-2-tosyloxymethyl acetoacetate and2-phenyl-2-(2-tosyloxyethyl)-1,3-dioxolane, but are not limited thereto.Of well-known photoacid generators, many of those compounds having poorstability, especially poor thermal stability exhibit an acidamplifier-like behavior.

In the resist composition of the invention, an appropriate amount of theacid amplifier compound is up to 2 parts, and especially up to 1 part byweight per 100 parts by weight of the base resin. Excessive amounts ofthe acid amplifier compound make diffusion control difficult, leading todegradation of resolution and pattern profile.

Organic Solvent

The organic solvent (C) used herein may be any organic solvent in whichthe base resin, acid generator, and other components are soluble.Illustrative, non-limiting, examples of the organic solvent includeketones such as cyclohexanone and methyl amyl ketone; alcohols such as3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether,ethylene glycol monomethyl ether, propylene glycol monoethyl ether,ethylene glycol monoethyl ether, propylene glycol dimethyl ether, anddiethylene glycol dimethyl ether; esters such as propylene glycolmonomethyl ether acetate (PGMEA), propylene glycol monoethyl etheracetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate,tert-butyl propionate, and propylene glycol mono-tert-butyl etheracetate; and lactones such as γ-butyrolactone. These solvents may beused alone or in combinations of two or more thereof. Of the aboveorganic solvents, it is recommended to use diethylene glycol dimethylether, 1-ethoxy-2-propanol, propylene glycol monomethyl ether acetate,and mixtures thereof because the acid generator is most soluble therein.

An appropriate amount of the organic solvent used is about 200 to 1,000parts, especially about 400 to 800 parts by weight per 100 parts byweight of the base resin.

Quencher

A quencher (D) may be optionally used in the resist composition of theinvention. The term “quencher” as used herein has a meaning generallyknown in the art and refers to a compound capable of suppressing therate of diffusion when the acid generated by the acid generator diffuseswithin the resist film. The inclusion of quencher facilitates adjustmentof resist sensitivity and holds down the rate of acid diffusion withinthe resist film, resulting in better resolution. In addition, itsuppresses changes in sensitivity following exposure and reducessubstrate and environment dependence, as well as improving the exposurelatitude and the pattern profile.

Examples of suitable quenchers include primary, secondary, and tertiaryaliphatic amines, mixed amines, aromatic amines, heterocyclic amines,nitrogen-containing compounds with carboxyl group, nitrogen-containingcompounds with sulfonyl group, nitrogen-containing compounds withhydroxyl group, nitrogen-containing compounds with hydroxyphenyl group,alcoholic nitrogen-containing compounds, amide derivatives, imidederivatives, carbamate derivatives, and ammonium salts.

Examples of suitable primary aliphatic amines include ammonia,methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine,isobutylamine, sec-butylamine, tert-butylamine, pentylamine,tert-amylamine, cyclopentylamine, hexylamine, cyclohexylamine,heptylamine, octylamine, nonylamine, decylamine, dodecylamine,cetylamine, methylenediamine, ethylenediamine, andtetraethylenepentamine. Examples of suitable secondary aliphatic aminesinclude dimethylamine, diethylamine, di-n-propylamine, diisopropylamine,di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine,dicyclopentylamine, dihexylamine, dicyclohexylamine, diheptylamine,dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine,N,N-dimethylmethylenediamine, N,N-dimethylethylenediamine, andN,N-dimethyltetraethylenepentamine. Examples of suitable tertiaryaliphatic amines include trimethylamine, triethylamine,tri-n-propylamine, triisopropylamine, tri-n-butylamine,triisobutylamine, tri-sec-butylamine, tripentylamine,tricyclopentylamine, trihexylamine, tricyclohexylamine, triheptylamine,trioctylamine, trinonylamine, tridecylamine, tridodecylamine,tricetylamine, N,N,N′,N′-tetramethylmethylenediamine,N,N,N′,N′-tetramethylethylenediamine, andN,N,N′,N′-tetramethyltetraethylenepentamine.

Examples of suitable mixed amines include dimethylethylamine,methylethylpropylamine, benzylamine, phenethylamine, andbenzyldimethylamine. Examples of suitable aromatic and heterocyclicamines include aniline derivatives (e.g., aniline, N-methylaniline,N-ethylaniline, N-propylaniline, N,N-dimethylaniline,N,N-bis(hydroxyethyl)aniline, 2-methylaniline, 3-methylaniline,4-methylaniline, ethylaniline, propylaniline, dimethylaniline,2,6-diisopropylaniline, trimethylaniline, 2-nitroaniline,3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline,3,5-dinitroaniline, and N,N-dimethyltoluidine), diphenyl(p-tolyl)amine,methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine,diaminonaphthalene, pyrrole derivatives (e.g., pyrrole, 2H-pyrrole,1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, andN-methylpyrrole), oxazole derivatives (e.g., oxazole and isooxazole),thiazole derivatives (e.g., thiazole and isothiazole), imidazolederivatives (e.g., imidazole, 4-methylimidazole, and4-methyl-2-phenylimidazole), pyrazole derivatives, furazane derivatives,pyrroline derivatives (e.g., pyrroline and 2-methyl-1-pyrroline),pyrrolidine derivatives (e.g., pyrrolidine, N-methylpyrrolidine,pyrrolidinone, and N-methylpyrrolidone), imidazoline derivatives,imidazolidine derivatives, pyridine derivatives (e.g., pyridine,methylpyridine, ethylpyridine, propylpyridine, butylpyridine,4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine,triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine,4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine,butoxypyridine, dimethoxypyridine, 4-pyrrolidinopyridine,2-(1-ethylpropyl)pyridine, aminopyridine, and dimethylaminopyridine),pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives,pyrazoline derivatives, pyrazolidine derivatives, piperidinederivatives, piperazine derivatives, morpholine derivatives, indolederivatives, isoindole derivatives, 1H-indazole derivatives, indolinederivatives, quinoline derivatives (e.g., quinoline and3-quinolinecarbonitrile), isoquinoline derivatives, cinnolinederivatives, quinazoline derivatives, quinoxaline derivatives,phthalazine derivatives, purine derivatives, pteridine derivatives,carbazole derivatives, phenanthridine derivatives, acridine derivatives,phenazine derivatives, 1,10-phenanthroline derivatives, adeninederivatives, adenosine derivatives, guanine derivatives, guanosinederivatives, uracil derivatives, and uridine derivatives.

Examples of suitable nitrogen-containing compounds with carboxyl groupinclude aminobenzoic acid, indolecarboxylic acid, and amino acidderivatives (e.g. nicotinic acid, alanine, alginine, aspartic acid,glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine,methionine, phenylalanine, threonine, lysine,3-aminopyrazine-2-carboxylic acid, and methoxyalanine). A typicalnitrogen-containing compound with sulfonyl group is 3-pyridinesulfonicacid. Examples of suitable nitrogen-containing compounds with hydroxylgroup, nitrogen-containing compounds with hydroxyphenyl group, andalcoholic nitrogen-containing compounds include 2-hydroxypyridine,aminocresol, 2,4-quinolinediol, 3-indolemethanol hydrate,monoethanolamine, diethanolamine, triethanolamine,N-ethyldiethanolamine, N,N-diethylethanolamine, triisopropanolamine,2,2′-iminodiethanol, 2-aminoethanol, 3-amino-1-propanol,4-amino-1-butanol, 4-(2-hydroxyethyl)morpholine,2-(2-hydroxyethyl)pyridine, 1-(2-hydroxyethyl)piperazine,1-[2-(2-hydroxyethoxy)ethyl]piperazine, piperidine ethanol,1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)-2-pyrrolidinone,3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol,8-hydroxyjulolidine, 3-quinuclidinol, 3-tropanol, 1-methyl-2-pyrrolidineethanol, 1-aziridine ethanol, N-(2-hydroxyethyl)phthalimide, andN-(2-hydroxyethyl)isonicotinamide. Examples of suitable amidederivatives include formamide, N-methylformamide, N,N-dimethylformamide,acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide,benzamide, and 1-cyclohexylpyrrolidone. Suitable imide derivativesinclude phthalimide, succinimide, and maleimide. Suitable carbamatederivatives include N-tert-butoxycarbonyl-N,N-dicyclohexylamine,N-tert-butoxycarbonylbenzimidazole, and oxazolidinone.

Suitable ammonium salts include pyridinium p-toluenesulfonate,triethylammonium p-toluenesulfonate, trioctylammoniump-toluenesulfonate, triethylammonium 2,4,6-triisopropylbenzenesulfonate,trioctylammonium 2,4,6-triisopropylbenzenesulfonate, triethylammoniumcamphorsulfonate, trioctylammonium camphorsulfonate, tetramethylammoniumhydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide,benzyltrimethylammonium hydroxide, tetramethylammoniump-toluenesulfonate, tetrabutylammonium p-toluenesulfonate,benzyltrimethylammonium p-toluenesulfonate, tetramethylammoniumcamphorsulfonate, tetrabutylammonium camphorsulfonate,benzyltrimethylammonium camphorsulfonate, tetramethylammonium2,4,6-triisopropylbenzenesulfonate, tetrabutylammonium2,4,6-triisopropylbenzenesulfonate, benzyltrimethylammonium2,4,6-triisopropylbenzenesulfonate, tetramethylammonium acetate,tetrabutylammonium acetate, benzyltrimethylammonium acetate,tetramethylammonium benzoate, tetrabutylammonium benzoate, andbenzyltrimethylammonium benzoate.

In addition, amine compounds of the following general formula (B)-1 mayalso be included alone or in admixture.N(X)_(n)(Y)_(3-n)  (B)-1In the formula, n is equal to 1, 2 or 3. The side chain X isindependently selected from groups of the following general formulas(X)-1 to (X)-3. The side chain Y is independently hydrogen or astraight, branched or cyclic C₁-C₂₀ alkyl group in which some or allhydrogen atoms may be substituted by fluorine atoms and which maycontain an ether or hydroxyl group. Two or three X may bond together toform a ring.

In the formulas, R³⁰⁰, R³⁰² and R³⁰⁵ are independently straight orbranched C₁-C₄ alkylene groups; R³⁰¹ and R³⁰⁴ are independently hydrogenor straight, branched or cyclic C₁-C₂₀ alkyl groups in which some or allhydrogen atoms may be substituted by fluorine atoms and which maycontain at least one hydroxyl group, ether group, ester group or lactonering; R³⁰³ is a single bond or a straight or branched C₁-C₄ alkylenegroup; R³⁰⁶ is a straight, branched or cyclic C₁-C₂₀ alkyl group inwhich some or all hydrogen atoms may be substituted by fluorine atomsand which may contain at least one hydroxyl group, ether group, estergroup or lactone ring.

Illustrative examples of the compounds of formula (B)-1 include, but arenot limited to, tris(2-methoxymethoxyethyl)amine,tris{(2-(2-methoxyethoxy)ethyl}amine,tris{2-(2-methoxyethoxymethoxy)ethyl}amine,tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine,tris{2-(1-ethoxypropoxy)ethyl}amine,tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine,4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane,4,7,13,18-tetraoxa-1,10-diazabicyclo[8.5.5]eicosane,1,4,10,13-tetraoxa-7,16-diazabicyclooctadecane, 1-aza-12-crown-4,1-aza-15-crown-5, 1-aza-18-crown-6, tris(2-formyloxyethyl)amine,tris(2-acetoxyethyl)amine, tris(2-propionyloxyethyl)amine,tris(2-butyryloxyethyl)amine, tris(2-isobutyryloxyethyl)amine,tris(2-valeryloxyethyl)amine, tris(2-pivaloyloxyethyl)amine,N,N-bis(2-acetoxyethyl)-2-(acetoxyacetoxy)ethylamine,tris(2-methoxycarbonyloxyethyl)amine,tris(2-tert-butoxycarbonyloxyethyl)amine,tris[2-(2-oxopropoxy)ethyl]amine,tris[2-(methoxycarbonylmethyl)oxyethyl]amine,tris[2-(tert-butoxycarbonylmethyloxy)ethyl]amine,tris[2-(cyclohexyloxycarbonylmethyloxy)ethyl]amine,tris(2-methoxycarbonylethyl)amine, tris(2-ethoxycarbonylethyl)amine,N,N-bis(2-hydroxyethyl)-2-(methoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(methoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(ethoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(ethoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(2-methoxyethoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(2-methoxyethoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(2-hydroxyethoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(2-acetoxyethoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-[(methoxycarbonyl)methoxycarbonyl]-ethylamine,N,N-bis(2-acetoxyethyl)-2-[(methoxycarbonyl)methoxycarbonyl]-ethylamine,N,N-bis(2-hydroxyethyl)-2-(2-oxopropoxycarbonyl)ethylamine,N,N-bis(2-acetoxyethyl)-2-(2-oxopropoxycarbonyl)ethylamine,N,N-bis(2-hydroxyethyl)-2-(tetrahydrofurfuryloxycarbonyl)-ethylamine,N,N-bis(2-acetoxyethyl)-2-(tetrahydrofurfuryloxycarbonyl)-ethylamine,N,N-bis(2-hydroxyethyl)-2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine,N,N-bis(2-acetoxyethyl)-2-[(2-oxotetrahydrofuran-3-yl)oxycarbonyl]ethylamine,N,N-bis(2-hydroxyethyl)-2-(4-hydroxybutoxycarbonyl)ethylamine,N,N-bis(2-formyloxyethyl)-2-(4-formyloxybutoxycarbonyl)-ethylamine,N,N-bis(2-formyloxyethyl)-2-(2-formyloxyethoxycarbonyl)-ethylamine,N,N-bis(2-methoxyethyl)-2-(methoxycarbonyl)ethylamine,N-(2-hydroxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(2-acetoxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(2-hydroxyethyl)-bis[2-(ethoxycarbonyl)ethyl]amine,N-(2-acetoxyethyl)-bis[2-(ethoxycarbonyl)ethyl]amine,N-(3-hydroxy-1-propyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(3-acetoxy-1-propyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-(2-methoxyethyl)-bis[2-(methoxycarbonyl)ethyl]amine,N-butyl-bis[2-(methoxycarbonyl)ethyl]amine,N-butyl-bis[2-(2-methoxyethoxycarbonyl)ethyl]amine,N-methyl-bis(2-acetoxyethyl)amine, N-ethyl-bis(2-acetoxyethyl)amine,N-methyl-bis(2-pivaloyloxyethyl)amine,N-ethyl-bis[2-(methoxycarbonyloxy)ethyl]amine,N-ethyl-bis[2-(tert-butoxycarbonyloxy)ethyl]amine,tris(methoxycarbonylmethyl)amine, tris(ethoxycarbonylmethyl)amine,N-butyl-bis(methoxycarbonylmethyl)amine,N-hexyl-bis(methoxycarbonylmethyl)amine, andβ-(diethylamino)-δ-valerolactone.

Also useful are one or more of cyclic structure-bearing amine compoundshaving the following general formula (B)-2.

Herein X is as defined above, and R³⁰⁷ is a straight or branched C₂-C₂₀alkylene group in which some or all hydrogen atoms may be substituted byfluorine atoms and which may contain one or more carbonyl, ether, esteror sulfide groups.

Illustrative examples of the cyclic structure-bearing amine compoundshaving formula (B)-2 include 1-[2-(methoxymethoxy)ethyl]pyrrolidine,1-[2-(methoxymethoxy)ethyl]piperidine,4-[2-(methoxymethoxy)ethyl]morpholine,1-[2-[(2-methoxyethoxy)methoxy]ethyl]pyrrolidine,1-[2-[(2-methoxyethoxy)methoxy]ethyl]piperidine,4-[2-[(2-methoxyethoxy)methoxy]ethyl]morpholine,2-[2-(2-methoxyethoxy)ethoxy]ethylmorpholine,2-[2-(2-butoxyethoxy)ethoxy]ethylmorpholine,2-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}ethylmorpholine,2-{2-[2-(2-butoxyethoxy)ethoxy]ethoxy}ethylmorpholine,2-(1-pyrrolidinyl)ethyl acetate, 2-piperidinoethyl acetate,2-morpholinoethyl acetate, 2-(1-pyrrolidinyl)ethyl formate,2-piperidinoethyl propionate, 2-morpholinoethyl acetoxyacetate,2-(1-pyrrolidinyl)ethyl methoxyacetate,4-[2-(methoxycarbonyloxy)ethyl]morpholine,1-[2-(t-butoxycarbonyloxy)ethyl]piperidine,4-[2-(2-methoxyethoxycarbonyloxy)ethyl]morpholine, methyl3-(1-pyrrolidinyl)propionate, methyl 3-piperidinopropionate, methyl3-morpholinopropionate, methyl 3-(thiomorpholino)propionate, methyl2-methyl-3-(1-pyrrolidinyl)propionate, ethyl 3-morpholinopropionate,methoxycarbonylmethyl 3-piperidinopropionate, 2-hydroxyethyl3-(1-pyrrolidinyl)propionate, 2-acetoxyethyl 3-morpholinopropionate,2-oxotetrahydrofuran-3-yl 3-(1-pyrrolidinyl)propionate,tetrahydrofurfuryl 3-morpholinopropionate, glycidyl3-piperidinopropionate, 2-methoxyethyl 3-morpholinopropionate,2-(2-methoxyethoxy)ethyl 3-(1-pyrrolidinyl)propionate, butyl3-morpholinopropionate, cyclohexyl 3-piperidinopropionate,α-(1-pyrrolidinyl)methyl-γ-butyrolactone, β-piperidino-γ-butyrolactone,β-morpholino-δ-valerolactone, methyl 1-pyrrolidinylacetate, methylpiperidinoacetate, methyl morpholinoacetate, methylthiomorpholinoacetate, ethyl 1-pyrrolidinylacetate, 2-methoxyethylmorpholinoacetate, 2-morpholinoethyl 2-methoxyacetate, 2-morpholinoethyl2-(2-methoxyethoxy)acetate, 2-morpholinoethyl2-[2-(2-methoxyethoxy)ethoxy]acetate, 2-morpholinoethyl hexanoate,2-morpholinoethyl octanoate, 2-morpholinoethyl decanoate,2-morpholinoethyl laurate, 2-morpholinoethyl myristate,2-morpholinoethyl palmitate, 2-morpholinoethyl stearate,2-morpholinoethyl cyclohexanecarboxylate, and 2-morpholinoethyladamantanecarboxylate.

Also, one or more of cyano-bearing amine compounds having the followinggeneral formulae (B)-3 to (B)-6 may be added.

Herein, X, R³⁰⁷ and n are as defined in formula (B)-1, and R³⁰⁸ and R³⁰⁹each are independently a straight or branched C₁-C₄ alkylene group.

Illustrative examples of the cyano-bearing amine compounds havingformulae (B)-3 to (B)-6 include 3-(diethylamino)propiononitrile,N,N-bis(2-hydroxyethyl)-3-aminopropiononitrile,N,N-bis(2-acetoxyethyl)-3-aminopropiononitrile,N,N-bis(2-formyloxyethyl)-3-aminopropiononitrile,N,N-bis(2-methoxyethyl)-3-aminopropiononitrile,N,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropiononitrile, methylN-(2-cyanoethyl)-N-(2-methoxyethyl)-3-aminopropionate, methylN-(2-cyanoethyl)-N-(2-hydroxyethyl)-3-aminopropionate, methylN-(2-acetoxyethyl)-N-(2-cyanoethyl)-3-aminopropionate,N-(2-cyanoethyl)-N-ethyl-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(2-hydroxyethyl)-3-aminopropiononitrile,N-(2-acetoxyethyl)-N-(2-cyanoethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(2-formyloxyethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(2-methoxyethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-[2-(methoxymethoxy)ethyl]-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(3-hydroxy-1-propyl)-3-aminopropiononitrile,N-(3-acetoxy-1-propyl)-N-(2-cyanoethyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-(3-formyloxy-1-propyl)-3-aminopropiononitrile,N-(2-cyanoethyl)-N-tetrahydrofurfuryl-3-aminopropiononitrile,N,N-bis(2-cyanoethyl)-3-aminopropiononitrile, diethylaminoacetonitrile,N,N-bis(2-hydroxyethyl)aminoacetonitrile,N,N-bis(2-acetoxyethyl)aminoacetonitrile,N,N-bis(2-formyloxyethyl)aminoacetonitrile,N,N-bis(2-methoxyethyl)aminoacetonitrile,N,N-bis[2-(methoxymethoxy)ethyl]aminoacetonitrile, methylN-cyanomethyl-N-(2-methoxyethyl)-3-aminopropionate, methylN-cyanomethyl-N-(2-hydroxyethyl)-3-aminopropionate, methylN-(2-acetoxyethyl)-N-cyanomethyl-3-aminopropionate,N-cyanomethyl-N-(2-hydroxyethyl)aminoacetonitrile,N-(2-acetoxyethyl)-N-(cyanomethyl)aminoacetonitrile,N-cyanomethyl-N-(2-formyloxyethyl)aminoacetonitrile,N-cyanomethyl-N-(2-methoxyethyl)aminoacetonitrile,N-cyanomethyl-N-[2-(methoxymethoxy)ethyl)aminoacetonitrile,N-cyanomethyl-N-(3-hydroxy-1-propyl)aminoacetonitrile,N-(3-acetoxy-1-propyl)-N-(cyanomethyl)aminoacetonitrile,N-cyanomethyl-N-(3-formyloxy-1-propyl)aminoacetonitrile,N,N-bis(cyanomethyl)aminoacetonitrile, 1-pyrrolidinepropiononitrile,1-piperidinepropiononitrile, 4-morpholinepropiononitrile,1-pyrrolidineacetonitrile, 1-piperidineacetonitrile,4-morpholineacetonitrile, cyanomethyl 3-diethylaminopropionate,cyanomethyl N,N-bis(2-hydroxyethyl)-3-aminopropionate, cyanomethylN,N-bis(2-acetoxyethyl)-3-aminopropionate, cyanomethylN,N-bis(2-formyloxyethyl)-3-aminopropionate, cyanomethylN,N-bis(2-methoxyethyl)-3-aminopropionate, cyanomethylN,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropionate, 2-cyanoethyl3-diethylaminopropionate, 2-cyanoethylN,N-bis(2-hydroxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis(2-acetoxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis(2-formyloxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis(2-methoxyethyl)-3-aminopropionate, 2-cyanoethylN,N-bis[2-(methoxymethoxy)ethyl]-3-aminopropionate, cyanomethyl1-pyrrolidinepropionate, cyanomethyl 1-piperidinepropionate, cyanomethyl4-morpholinepropionate, 2-cyanoethyl 1-pyrrolidinepropionate,2-cyanoethyl 1-piperidinepropionate, and 2-cyanoethyl4-morpholinepropionate.

Also included are amine compounds having an imidazole structure and apolar functional group, represented by the general formula (B)-7.

Herein, R³¹⁰ is a straight, branched or cyclic C₂-C₂₀ alkyl group inwhich some or all hydrogen atoms may be substituted by fluorine atomsand which has one or more polar functional groups. The polar functionalgroup is selected from among hydroxyl, carbonyl, ester, ether, sulfide,carbonate, cyano and acetal groups and mixtures thereof. R³¹¹, R³¹² andR³¹³ are each independently a hydrogen atom, a straight, branched orcyclic C₁-C₁₀ alkyl group, aryl group or aralkyl group.

Also included are amine compounds having a benzimidazole structure and apolar functional group, represented by the general formula (B)-8.

Herein, R³¹⁴ is a hydrogen atom, a straight, branched or cyclic C₁-C₁₀alkyl group, aryl group or aralkyl group. R³¹⁵ is a straight, branchedor cyclic C₁-C₂₀ alkyl group in which some or all hydrogen atoms may besubstituted by fluorine atoms and which has one or more polar functionalgroups. The alkyl group contains as the polar functional group at leastone group selected from among ester, acetal and cyano groups, and mayadditionally contain at least one group selected from among hydroxyl,carbonyl, ether, sulfide and carbonate groups.

Further included are heterocyclic nitrogen-containing compounds having apolar functional group, represented by the general formulae (B)-9 and(B)-10.

Herein, A is a nitrogen atom or ≡C—R³²². B is a nitrogen atom or≡C—R³²³. R³¹⁶ is a straight, branched or cyclic C₂-C₂₀ alkyl group inwhich some or all hydrogen atoms may be substituted by fluorine atomsand which has one or more polar functional groups, the polar functionalgroup being selected from among hydroxyl, carbonyl, ester, ether,sulfide, carbonate, cyano and acetal groups and mixtures thereof. R³¹⁷,R³¹⁸, R³¹⁹ and R³²⁰ are each independently a hydrogen atom, a straight,branched or cyclic C₁-C₁₀ alkyl group or aryl group, or a pair of R³¹⁷and R³¹⁸ and a pair of R³¹⁹ and R³²⁰, taken together, may form abenzene, naphthalene or pyridine ring. R³²¹ is a hydrogen atom, astraight, branched or cyclic C₁-C₁₀ alkyl group or aryl group. R³²² andR³²³ each are a hydrogen atom, a straight, branched or cyclic C₁-C₁₀alkyl group or aryl group, or a pair of R³²¹ and R³²³, taken together,may form a benzene or naphthalene ring.

Also included are organic nitrogen-containing compounds having anaromatic carboxylic acid ester structure, represented by the generalformulae (B)-11 to (B)-14.

Herein R³²⁴ is a C₆-C₂₀ aryl group or C₄-C₂₀ hetero-aromatic group, inwhich some or all hydrogen atoms may be replaced by halogen atoms,straight, branched or cyclic C₁-C₂₀ alkyl groups, C₆-C₂₀ aryl groups,C₇-C₂₀ aralkyl groups, C₁-C₁₀ alkoxy groups, C₁-C₁₀ acyloxy groups orC₁-C₁₀ alkylthio groups. R³²⁵ is CO₂R³²⁶, OR³²⁷ or cyano group. R³²⁶ isa C₁-C₁₀ alkyl group, in which some methylene groups may be replaced byoxygen atoms. R³²⁷ is a C₁-C₁₀ alkyl or acyl group, in which somemethylene groups may be replaced by oxygen atoms. R³²⁸ is a single bond,methylene, ethylene, sulfur atom or —O(CH₂CH₂O)_(n)— group wherein n is0, 1, 2, 3 or 4. R³²⁹ is hydrogen, methyl, ethyl or phenyl. X is anitrogen atom or CR³³⁰. Y is a nitrogen atom or CR³³¹. Z is a nitrogenatom or CR³³². R³³⁰, R³³¹ and R³³² are each independently hydrogen,methyl or phenyl. Alternatively, a pair of R³³⁰ and R³³¹ or a pair ofR³³¹ and R³³² may bond together to form a C₆-C₂₀ aromatic ring or C₂-C₂₀hetero-aromatic ring.

Further included are amine compounds of 7-oxanorbornane-2-carboxylicester structure, represented by the general formula (B)-15.

Herein R³³³ is hydrogen or a straight, branched or cyclic C₁-C₁₀ alkylgroup. R³³⁴ and R³³⁵ are each independently a C₁-C₂₀ alkyl group, C₆-C₂₀aryl group or C₇-C₂₀ aralkyl group, which may contain one or more polarfunctional groups selected from among ether, carbonyl, ester, alcohol,sulfide, nitrile, amine, imine, and amide and in which some hydrogenatoms may be replaced by halogen atoms. R³³⁴ and R³³⁵, taken together,may form a heterocyclic or hetero-aromatic ring of 2 to 20 carbon atoms.

The quenchers may be used alone or in admixture of two or more. Thequencher is preferably formulated in an amount of 0.001 to 2 parts, andespecially 0.01 to 1 part by weight, per 100 parts by weight of thetotal base resin. Less than 0.001 phr of the quencher may achieve noaddition effect whereas more than 2 phr may lead to too low asensitivity.

Surfactant

Optionally, the resist composition of the invention may further comprisea surfactant which is commonly used for improving the coatingcharacteristics. The surfactant may be added in conventional amounts solong as this does not compromise the objects of the invention.

Nonionic surfactants are preferred, examples of which includeperfluoroalkylpolyoxyethylene ethanols, fluorinated alkyl esters,perfluoroalkylamine oxides, perfluoroalkyl EO-addition products, andfluorinated organosiloxane compounds. Useful surfactants arecommercially available under the trade names Fluorad FC-430 and FC-431from Sumitomo 3M, Ltd., Surflon S-141, S-145, KH-10, KH-20, KH-30 andKH-40 from Asahi Glass Co., Ltd., Unidyne DS-401, DS-403 and DS-451 fromDaikin Industry Co., Ltd., Megaface F-8151 from Dai-Nippon Ink &Chemicals, Inc., and X-70-092 and X-70-093 from Shin-Etsu Chemical Co.,Ltd. Preferred surfactants are Fluorad FC-430 from Sumitomo 3M, Ltd.,KH-20 and KH-30 from Asahi Glass Co., Ltd., and X-70-093 from Shin-EtsuChemical Co., Ltd. The surfactant is preferably compounded in an amountof 0.01 to 1 part, and especially 0.05 to 0.5 part by weight, per 100parts by weight of the total base resin.

While the resist composition of the invention typically comprises apolymer or base resin, acid generator, organic solvent and quencher asdescribed above, there may be added optional other ingredients such asdissolution inhibitors, acidic compounds, stabilizers, and dyes.Optional ingredients may be added in conventional amounts so long asthis does not compromise the objects of the invention.

Pattern formation using the resist composition of the invention may becarried out by a known lithographic technique. For example, the resistcomposition is applied onto a substrate such as a silicon wafer by spincoating or the like to form a resist film having a thickness of 0.05 to2.0 μm, which is then pre-baked on a hot plate at 60 to 150° C. for 1 to10 minutes, and preferably at 80 to 140° C. for 1 to 5 minutes. Apatterning mask having the desired pattern is then placed over theresist film, and the film exposed through the mask to an electron beamor to high-energy radiation such as deep-UV ray, excimer laser, or x-rayin a dose of about 1 to 200 mJ/cm², and preferably about 10 to 100mJ/cm². Light exposure may be done by a conventional exposure process orin some cases, by an immersion process of providing liquid impregnationbetween the mask and the resist. The resist film is then post-exposurebaked (PEB) on a hot plate at 60 to 150° C. for 1 to 5 minutes, andpreferably at 80 to 140° C. for 1 to 3 minutes. Finally, development iscarried out using as the developer an aqueous alkali solution, such as a0.1 to 5 wt % (preferably 2 to 3 wt %) aqueous solution oftetramethylammonium hydroxide (TMAH), this being done by a conventionalmethod such as dip, puddle, or spray development for a period of 0.1 to3 minutes, and preferably 0.5 to 2 minutes. These steps result in theformation of the desired pattern on the substrate. Of the various typesof high-energy radiation that may be used, the resist composition of theinvention is best suited to fine pattern formation with, in particular,deep-UV rays having a wavelength of 250 to 190 nm, an excimer laser,x-rays, or an electron beam. The desired pattern may not be obtainableoutside the upper and lower limits of the above range.

EXAMPLE

Examples and Comparative Examples are given below by way of illustrationand not by way of limitation. The abbreviation Mw is a weight averagemolecular weight as measured by GPC using polystyrene standards.

Example 1

Lactone-containing compounds within the scope of the invention weresynthesized according to the following formulation.

Example 1-1 Synthesis of Monomer 1

Example 1-1-1 Synthesis of7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-chloroacetate

In 180 ml of tetrahydrofuran were dissolved 25.0 g of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylateand 16.0 g of 2-chloroacetic acid chloride. To the solution below 20°C., 10.7 g of pyridine was added dropwise. The solution was stirred atroom temperature for 1 hour and combined with 40 g of a 5% aqueoussolution of sodium hydrogen carbonate, followed by ordinarypost-treatment. Recrystallization from isopropyl ether gave 31.5 g ofthe target compound (yield 93%).

¹H-NMR (600 MHz in CDCl₃): δ=1.69 (1H, dd), 2.07 (1H, d), 2.80 (1H, m),2.84 (1H, dd), 3.11 (1H, dd), 3.35 (1H, t-like), 3.73 (3H, s), 4.06 (2H,s), 4.63 (1H, d), 5.34 (1H, s) ppm.

Example 1-1-2 Synthesis in one route of7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)-acetate

A mixture of 28.9 g of the 2-chloroacetic ester obtained in Example1-1-1 and 40 g of dimethylformamide was added dropwise to a mixture of12.4 g of sodium methacrylate, 3.0 g of sodium iodide and 50 g ofdimethylformamide at a temperature below 30° C. The mixture was stirredat the temperature for 8 hours. 100 ml of water was added below 30° C.This was followed by ordinary post-treatment and recrystallization fromtoluene and n-hexane, obtaining 29.1 g of the target compound (yield86%).

IR (thin film): ν=3002, 2958, 1779, 1758, 1733, 1722, 1436, 1371,1340,1220, 1205, 1199, 1155, 1052, 1006 cm⁻¹

¹H-NMR (600 MHz in CDCl₃): δ=1.67 (1H, dd), 1.96 (3H, m), 2.01 (1H, d,),2.80 (1H, m), 2.82 (1H, dd), 3.08 (1H, dd), 3.32 (1H, t-like), 3.72 (3H,s), 4.61 (1H, d), 4.66 (2H, s), 5.33 (1H, s), 5.66 (1H, m), 6.20 (1H, s)ppm

Example 1-1-3 Synthesis in another route of7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate

A mixture of 28.9 g of the 2-chloroacetic ester obtained in Example1-1-1 and 40 g of dimethylformamide was added dropwise to a mixture of9.2 g of methacrylic acid, 16.2 g of potassium carbonate, 3.0 g ofsodium iodide, and 50 g of dimethylformamide at a temperature below 30°C. The mixture was stirred at the temperature for 8 hours. 100 ml ofwater was added below 30° C. This was followed by ordinarypost-treatment and recrystallization from toluene and n-hexane,obtaining 28.1 g of the target compound (yield 83%). The spectroscopicdata of this compound were exactly identical with those of the compoundsynthesized in Example 1-1-2.

Example 1-2 Synthesis of Monomer 2

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from usingacrylic acid instead of methacrylic acid. There was obtained7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(acryloyloxy)acetate. Two-step yield 80%.

Example 1-3 Synthesis of Monomer 3

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using2-(trifluoromethyl)acrylic acid instead of methacrylic acid. There wasobtained7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-[2-(trifluoromethyl)acryloyloxy]acetate. Two-step yield 74%.

Example 1-4 Synthesis of Monomer 4

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from usingethyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate.There was obtained7-ethoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate. Two-step yield 78%.

Example 1-5 Synthesis of Monomer 5 Example 1-5-1 Synthesis of2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl2-chloroacetate

The target compound was obtained by the same procedure as in Example1-1-1 aside from using6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan insteadof methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate.Yield 91%.

¹H-NMR (600 MHz in DMSO-d6): δ=2.04-2.12 (2H, m), 2.68-2.73 (1H, m),4.41 (2H, dd-like), 4.66 (1H, d), 4.70 (1H, d), 4.85 (1H, s), 5.44 (1H,t) ppm

Example 1-5-2 Synthesis of2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl2-(methacryloyloxy)acetate

The target compound was obtained by the same procedure as in Example1-1-2 aside from using2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-chloroacetate instead of7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-chloroacetate. Yield 81%.

IR (thin film): ν=2989, 2960, 1791, 1762, 1724, 1454, 1421, 1326, 1299,1230, 1182, 1157, 1047, 1024, 811 cm⁻¹

¹H-NMR (600 MHz in CDCl₃): δ=1.97 (3H, m), 2.07 (1H, dd), 2.25 (1H, m),2.76 (1H, m), 4.65 (1H, d), 4.70 (2H, s), 4.72 (1H, d), 4.81 (1H, s),5.36 (1H, t), 5.67 (1H, m), 6.21 (1H, m) ppm

Example 1-6 Synthesis of Monomer 6

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan insteadof methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateand acrylic acid instead of methacrylic acid. There was obtained2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(acryloyloxy)acetate. Two-step yield 77%.

Example 1-7 Synthesis of Monomer 7

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan insteadof methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateand 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. Therewas obtained 2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-[2-(trifluoromethyl)acryloyloxy]-acetate. Two-step yield 73%.

Example 1-8 Synthesis of Monomer 8

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from usingtert-butyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate.There was obtained7-tert-butoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate. Two-step yield 79%.

Example 1-9 Synthesis of Monomer 9

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from usingtert-butyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateand acrylic acid instead of methacrylic acid. There was obtained7-tert-butoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(acryloyloxy)acetate. Two-step yield 77%.

Example 1-10 Synthesis of Monomer 10

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from usingcyclohexyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate.There was obtained7-cyclohexyloxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate. Two-step yield 82%.

Example 1-11 Synthesis of Monomer 11

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from usingcyclohexyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateand acrylic acid instead of methacrylic acid. There was obtained7-cyclohexyloxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(acryloyloxy)-acetate. Two-step yield 79%.

Example 1-12 Synthesis of Monomer 12

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from usingcyclohexyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateand 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. Therewas obtained7-cyclohexyloxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-[2-(trifluoromethyl)acryloyloxy]acetate. Two-step yield 73%.

Example 1-13 Synthesis of Monomer 13 Example 1-13-1 Synthesis of7-(1-ethyl-1-cyclopentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-chloroacetate

The target compound was obtained by the same procedure as in Example1-1-1 aside from using 1-ethyl-1-cyclopentyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate.Yield 91%.

¹H-NMR (600 MHz in CDCl₃): δ=0.85 (3H, t), 1.56-1.71 (6H, m), 1.78 (1H,dd), 1.89-2.12 (5H, m), 2.70 (1H, s), 2.86 (1H, s), 3.09 (1H, d), 3.23(1H, dt-like), 4.07 (2H, s), 4.56 (1H, d), 4.70 (1H, d) ppm

Example 1-13-2 Synthesis of7-(1-ethyl-1-cyclopentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyl-oxy)acetate

The target compound was obtained by the same procedure as in Example1-1-2 aside from using7-(1-ethyl-1-cyclo-pentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl2-chloroacetate instead of7-methoxycarbonyl-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-yl2-chloroacetate. Yield 76%.

IR (thin film): ν=2979, 2960, 2929, 1795, 1787, 1764, 1727, 1459, 1367,1303, 1251, 1211, 1176, 1160, 1112, 1006 cm⁻¹

¹H-NMR (600 MHz in CDCl₃): δ=0.84 (3H, t), 1.56-1.71 (6H, m), 1.77 (1H,dd), 1.85-2.12 (8H, m), 2.68 (1H, s), 2.84 (1H, s), 3.07 (1H, d), 3.20(1H, dt-like), 4.53 (1H, d), 4.68 (2H, s), 4.70 (1H, d), 5.68 (1H, m),6.21 (1H, m) ppm

Example 1-14 Synthesis of Monomer 14

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using1-ethyl-1-cyclopentyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylateand 2-(trifluoromethyl)acrylic acid instead of methacrylic acid. Therewas obtained7-(1-ethyl-1-cyclopentyloxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-[2-(trifluoromethyl)acryloyloxy]-acetate. Two-step yield 71%.

Example 1-15 Synthesis of Monomer 15

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from usingmethyl6-hydroxy-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate.There was obtained7-methoxycarbonyl-2-oxo-4-oxahexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate. Two-step yield 74%.

Example 1-16 Synthesis of Monomer 16

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using2,2,2-trifluoroethyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylate.There was obtained7-(2,2,2-trifluoroethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate. Two-step yield 77%.

Example 1-17 Synthesis of Monomer 17

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using2,2,2-trifluoroethyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[(b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-7-carboxylateand acrylic acid instead of methacrylic acid. There was obtained7-(2,2,2-trifluoro-ethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta-[b]furan-6-yl2-(acryloyloxy)acetate. Two-step yield 72%.

Example 1-18 Synthesis of Monomer 18

The procedure of Examples 1-1-1 and 1-1-2 was repeated aside from using2-methoxyethyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylate.There was obtained7-(2-methoxyethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(methacryloyloxy)acetate. Two-step yield 78%.

Example 1-19 Synthesis of Monomer 19

The procedure of Examples 1-1-1 and 1-1-3 was repeated aside from using2-methoxyethyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateinstead of methyl6-hydroxy-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-7-carboxylateand acrylic acid instead of methacrylic acid. There was obtained7-(2-methoxyethoxycarbonyl)-2-oxohexahydro-3,5-methano-2H-cyclopenta[b]furan-6-yl2-(acryloyloxy)-acetate. Two-step yield 75%.

Example 2

Polymers within the scope of the invention were synthesized according tothe following formulation.

Example 2-1 Synthesis of Polymer 1

In 70.0 g of methyl ethyl ketone were dissolved 22.1 g of Monomer 1,17.9 g of 3-ethyl-3-exo-tetracyclo-[4.4.0.1^(2,5).1^(7,10)]dodecanylmethacrylate, and 858 mg of 2,2′-azobisisobutyronitrile. In a nitrogenatmosphere, this solution was added dropwise over 4 hours to 23.3 g ofmethyl ethyl ketone which was stirred at 80° C. The solution was stirredat 80° C. for a further 2 hours. The reaction solution was cooled toroom temperature, and with vigorous stirring, added dropwise to 640 g ofmethanol. The resulting solids were collected by filtration and dried invacuum at 50° C. for 15 hours, obtaining a white powder solid designatedPolymer 1. The amount was 32.4 g in a yield of 81%. Polymer 1 had acomposition and Mw shown below.

Examples 2-2 to 2-35 and Comparative Examples 1-1 to 1-3 Synthesis ofPolymers 2-38

Polymers 2 to 38 were synthesized by the same procedure as Examples 2-1except that the type and proportion of monomers were changed, with theircompositional proportion (in molar ratio) and Mw being shown in Table 1.The structure of the units is shown in Tables 2 to 5.

TABLE 1 Unit 1 Unit 2 Unit 3 Unit 4 Resin (ratio) (ratio) (ratio)(ratio) Mw Example 2-1 Polymer 1 L-1M (0.50) A-1M (0.50) — — 7,100Example 2-2 Polymer 2 L-2M (0.50) A-1M (0.50) — — 6,900 Example 2-3Polymer 3 L-3M (0.50) A-1M (0.50) — — 7,300 Example 2-4 Polymer 4 L-4M(0.50) A-1M (0.50) — — 7,200 Example 2-5 Polymer 5 L-5M (0.50) A-1M(0.50) — — 7,400 Example 2-6 Polymer 6 L-1M (0.55) A-1M (0.30) B-1M(0.15) — 7,100 Example 2-7 Polymer 7 L-1M (0.50) A-2M (0.35) B-1M (0.15)— 7,400 Example 2-8 Polymer 8 L-1M (0.55) A-3M (0.30) B-1M (0.15) —6,900 Example 2-9 Polymer 9 L-1M (0.55) A-4M (0.30) B-1M (0.15) — 7,300Example 2-10 Polymer 10 L-1M (0.50) A-5M (0.35) B-1M (0.15) — 6,500Example 2-11 Polymer 11 L-1M (0.50) A-6M (0.35) B-1M (0.15) — 7,000Example 2-12 Polymer 12 L-2M (0.55) A-1M (0.30) B-1M (0.15) — 7,300Example 2-13 Polymer 13 L-2M (0.50) A-2M (0.35) B-1M (0.15) — 7,500Example 2-14 Polymer 14 L-2M (0.55) A-3M (0.30) B-1M (0.15) — 7,000Example 2-15 Polymer 15 L-2M (0.55) A-4M (0.30) B-1M (0.15) — 7,400Example 2-16 Polymer 16 L-2M (0.50) A-5M (0.35) B-1M (0.15) — 6,600Example 2-17 Polymer 17 L-2M (0.50) A-6M (0.35) B-1M (0.15) — 7,100Example 2-18 Polymer 18 L-1M (0.55) A-1M (0.30) B-2M (0.15) — 6,700Example 2-19 Polymer 19 L-1M (0.55) A-1M (0.30) B-1A (0.15) — 6,800Example 2-20 Polymer 20 L-1M (0.30) A-1M (0.30) B-1M (0.15) B-3M (0.25)6,800 Example 2-21 Polymer 21 L-1M (0.30) A-1M (0.30) B-1M (0.15) B-4M(0.25) 6,700 Example 2-22 Polymer 22 L-1M (0.30) A-1M (0.30) B-1M (0.15)B-5M (0.25) 6,600 Example 2-23 Polymer 23 L-1M (0.30) A-1M (0.30) B-1M(0.15) B-6M (0.25) 6,700 Example 2-24 Polymer 24 L-1M (0.30) A-2M (0.35)B-1M (0.15) B-6M (0.20) 6,500 Example 2-25 Polymer 25 L-1M (0.30) A-3M(0.30) B-1M (0.15) B-6M (0.25) 6,900 Example 2-26 Polymer 26 L-1M (0.30)A-4M (0.30) B-1M (0.15) B-6M (0.25) 7,000 Example 2-27 Polymer 27 L-1M(0.30) A-5M (0.35) B-1M (0.15) B-6M (0.20) 7,300 Example 2-28 Polymer 28L-1M (0.30) A-6M (0.35) B-1M (0.15) B-6M (0.20) 7,200 Example 2-29Polymer 29 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-1M (0.10) 7,000 Example2-30 Polymer 30 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-2M (0.10) 6,800Example 2-31 Polymer 31 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-3M (0.10)6,900 Example 2-32 Polymer 32 L-1M (0.45) A-1M (0.30) B-1M (0.15) C-4M(0.10) 6,800 Example 2-33 Polymer 33 L-1M (0.45) A-1M (0.30) B-1M (0.15)C-5M (0.10) 6,700 Example 2-34 Polymer 34 L-2M (0.30) A-1M (0.30) B-1M(0.15) B-6M (0.25) 6,800 Example 2-35 Polymer 35 L-2M (0.30) A-3M (0.30)B-1M (0.15) B-6M (0.25) 7,300 Comparative Polymer 36 — A-3M (0.30) B-1M(0.15) B-4M (0.55) 6,900 Example 1-1 Comparative Polymer 37 — A-3M(0.30) B-1M (0.15) B-6M (0.55) 6,600 Example 1-2 Comparative Polymer 38— A-3M (0.30) B-1M (0.15) B-7M (0.55) 7,200 Example 1-3

TABLE 2 L-1M (R = CH₃) L-2M (R = CH₃) L-1A (R = H) L-2A (R = H)

L-3M (R = CH₃) L-4M (R = CH₃) L-3A (R = H) L-4A (R = H)

L-5M (R = CH₃) L-5A (R = H)

TABLE 3 A-1M (R = CH₃) A-2M (R = CH₃) A-1A (R = H) A-2A (R = H)

A-3M (R = CH₃) A-4M (R = CH₃) A-3A (R = H) A-4A (R = H)

A-5M (R = CH₃) A-6M (R = CH₃) A-5A (R = H) A-6A (R = H)

TABLE 4 B-1M (R = CH₃) B-2M (R = CH₃) B-1A (R = H) B-2A (R = H)

B-3M (R = CH₃) B-4M (R = CH₃) B-3A (R = H) B-4A (R = H)

B-5M (R = CH₃) B-6M (R = CH₃) B-5A (R = H) B-6A (R = H)

B-7M (R = CH₃) B-7A (R = H)

TABLE 5 C-1M (R = CH₃) C-2M (R = CH₃) C-1A (R = H) C-2A (R = H)

C-3M (R = CH₃) C-4M (R = CH₃) C-3A (R = H) C-4A (R = H)

C-5M (R = CH₃) C-5A (R = H)

Preparation of Resist Compositions Examples 3-1 to 3-59 & ComparativeExamples 2-1 to 2-3

Resist compositions were prepared by using inventive resins (Polymer 1to 35, abbreviated P01 to P35) or comparative resins (Polymers 36 to 38,abbreviated P36 to P38) as the base resin, and dissolving the polymer,an acid generator (PAG), and a quencher (Base) in a solvent mixture(PGMEA and CyHO) containing 0.01 wt % of surfactant KH-20 (Asahi GlassCo., Ltd.) in accordance with the recipe shown in Table 6. Thesecompositions were each filtered through a Teflon® filter having a porediameter 0.2 μm, thereby giving inventive resist solutions (R-01 to 59)and comparative resist solutions (R-60 to 62).

TABLE 6 Resin PAG Base Solvent 1 Solvent 2 Resist (pbw) (pbw) (pbw)(pbw) (pbw) Example 3-1 R-01 Polymer 01 (80) PAG-1 (4.4) Base-1 (0.94)PGMEA (560) CyHO (240) Example 3-2 R-02 Polymer 02 (80) PAG-1 (4.4)Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-3 R-03 Polymer 03 (80)PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-4 R-04Polymer 04 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-5 R-05 Polymer 05 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-6 R-06 Polymer 06 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-7 R-07 Polymer 07 (80) PAG-1 (4.4) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-8 R-08 Polymer 08 (80) PAG-1(4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-9 R-09 Polymer 09(80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-10 R-10Polymer 10 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-11 R-11 Polymer 11 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-12 R-12 Polymer 12 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-13 R-13 Polymer 13 (80) PAG-1 (4.4) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-14 R-14 Polymer 14 (80) PAG-1(4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-15 R-15 Polymer 15(80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-16 R-16Polymer 16 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-17 R-17 Polymer 17 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-18 R-18 Polymer 18 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-19 R-19 Polymer 19 (80) PAG-1 (4.4) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-20 R-20 Polymer 20 (80) PAG-1(4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-21 R-21 Polymer 21(80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-22 R-22Polymer 22 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-23 R-23 Polymer 23 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-24 R-24 Polymer 24 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-25 R-25 Polymer 25 (80) PAG-1 (4.4) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-26 R-26 Polymer 26 (80) PAG-1(4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-27 R-27 Polymer 27(80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-28 R-28Polymer 28 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-29 R-29 Polymer 29 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-30 R-30 Polymer 30 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-31 R-31 Polymer 31 (80) PAG-1 (4.4) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-32 R-32 Polymer 32 (80) PAG-1(4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-33 R-33 Polymer 33(80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-34 R-34Polymer 34 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-35 R-35 Polymer 35 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-36 R-36 Polymer 06 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-37 R-37 Polymer 12 (80) PAG-2 (4.9) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-38 R-38 Polymer 23 (80) PAG-2(4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-39 R-39 Polymer 25(80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-40 R-40Polymer 34 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-41 R-41 Polymer 35 (80) PAG-2 (4.9) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-42 R-42 Polymer 06 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA(560) CyHO (240) Example 3-43 R-43 Polymer 12 (80) PAG-3 (4.7) Base-1(0.94) PGMEA (560) CyHO (240) Example 3-44 R-44 Polymer 23 (80) PAG-3(4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-45 R-45 Polymer 25(80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example 3-46 R-46Polymer 34 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO (240) Example3-47 R-47 Polymer 35 (80) PAG-3 (4.7) Base-1 (0.94) PGMEA (560) CyHO(240) Example 3-48 R-48 Polymer 06 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA(560) CyHO (240) PAG-3 (2.3) Example 3-49 R-49 Polymer 12 (80) PAG-1(2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-50 R-50Polymer 23 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3(2.3) Example 3-51 R-51 Polymer 25 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA(560) CyHO (240) PAG-3 (2.3) Example 3-52 R-52 Polymer 34 (80) PAG-1(2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3 (2.3) Example 3-53 R-53Polymer 35 (80) PAG-1 (2.2) Base-1 (0.94) PGMEA (560) CyHO (240) PAG-3(2.3) Example 3-54 R-54 Polymer 06 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA(560) CyHO (240) Example 3-55 R-55 Polymer 12 (80) PAG-1 (4.4) Base-2(0.74) PGMEA (560) CyHO (240) Example 3-56 R-56 Polymer 23 (80) PAG-1(4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-57 R-57 Polymer 25(80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example 3-58 R-58Polymer 34 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO (240) Example3-59 R-59 Polymer 35 (80) PAG-1 (4.4) Base-2 (0.74) PGMEA (560) CyHO(240) Comparative Example 2-1 R-60 Polymer 36 (80) PAG-1 (4.4) Base-1(0.94) PGMEA (560) CyHO (240) Comparative Example 2-2 R-61 Polymer 37(80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560) CyHO (240) ComparativeExample 2-3 R-62 Polymer 38 (80) PAG-1 (4.4) Base-1 (0.94) PGMEA (560)CyHO (240)

The acid generator, quencher (base) and solvent shown in Table 6 havethe following meanings.

-   PAG-1: triphenylsulfonium nonafluorobutanesulfonate-   PAG-2: 4-t-butoxyphenyldiphenylsulfonium nonafluorobutanesulfonate-   PAG-3: triphenylsulfonium    1,1,3,3,3-pentafluoro-2-cyclohexylcarboxypropanesulfonate-   Base-1: tri(2-methoxymethoxyethyl)amine-   Base-2: 2-(2-methoxyethoxymethoxy)ethylmorpholine-   PGMEA: 1-methoxyisopropyl acetate-   CyHO: cyclohexanone

Evaluation of Resolution and Line Edge Roughness Examples 4-1 to 4-59 &Comparative Examples 3-1 to 3-4

Each of inventive resist compositions (R-01 to 59) and comparativeresist compositions (R-60 to 62) was spin coated on a silicon waferhaving an antireflective coating (ARC-29A, Nissan Chemical Co., Ltd.) of78 nm thick and baked at 110° C. for 60 seconds, forming a resist filmof 170 nm thick. The wafer was exposed by means of an ArF excimer laserstepper (Nikon Corp., NA 0.85), post-exposure baked (PEB) for 60seconds, and puddle developed with a 2.38 wt % tetramethylammoniumhydroxide aqueous solution for 30 seconds, forming a 1:1 line-and-spacepattern and a 1:10 isolated line pattern. During the PEB, an optimumtemperature for each resist composition was employed.

The patterned wafer was observed under a top-down scanning electronmicroscope (TDSEM). The optimum exposure (Eop) was defined as theexposure dose (mJ/cm²) which provided a 1:1 resolution at the top andbottom of a 90-nm 1:1 line-and-space pattern. The maximum resolution ofthe resist was defined as the minimum line width (on-mask size, inincrements of 5 nm) of a 1:1 line-and-space pattern that was resolvedand separated at the optimum exposure, with smaller values indicatingbetter resolution. The 1:10 isolated line pattern at the optimumexposure was also observed for determining an actual on-wafer size ofthe isolated line pattern with an on-mask size of 140 nm, which wasreported as mask fidelity (on-wafer size, a larger size being better).Further, a line portion of the 90-nm 1:1 line-and-space pattern wasexamined for line edge roughness (LER). For each of left and right edgesof a line, measurement was made at 16 points along a measurement regionof 300 nm long. Provided that L and R represent averages of fluctuationsof measurement points from the center line along the left and rightedges, respectively, a square root of (L²+R²) is reported as LER (in nm,smaller fluctuation being better).

Table 7 tabulates the test results (maximum resolution, mask fidelityand LER) of the inventive and comparative resist compositions.

TABLE 7 Maximum Mask Resist PEB temp. Eop resolution fidelity LERExample 4-1 R-01  95° C. 41.0 mJ/cm² 75 nm 85 nm 5.4 nm Example 4-2 R-02 95° C. 43.0 mJ/cm² 75 nm 88 nm 5.7 nm Example 4-3 R-03  95° C. 39.0mJ/cm² 75 nm 84 nm 5.3 nm Example 4-4 R-04  95° C. 38.0 mJ/cm² 75 nm 83nm 5.1 nm Example 4-5 R-05  95° C. 36.0 mJ/cm² 80 nm 83 nm 5.1 nmExample 4-6 R-06 105° C. 40.0 mJ/cm² 70 nm 84 nm 5.0 nm Example 4-7 R-07120° C. 42.0 mJ/cm² 75 nm 85 nm 5.5 nm Example 4-8 R-08 105° C. 42.0mJ/cm² 70 nm 85 nm 5.2 nm Example 4-9 R-09 120° C. 41.0 mJ/cm² 75 nm 83nm 5.4 nm Example 4-10 R-10 105° C. 43.0 mJ/cm² 70 nm 80 nm 5.0 nmExample 4-11 R-11 105° C. 43.0 mJ/cm² 70 nm 86 nm 4.9 nm Example 4-12R-12 105° C. 42.0 mJ/cm² 70 nm 87 nm 5.2 nm Example 4-13 R-13 120° C.45.0 mJ/cm² 70 nm 87 nm 5.6 nm Example 4-14 R-14 105° C. 44.0 mJ/cm² 70nm 89 nm 5.4 nm Example 4-15 R-15 120° C. 43.0 mJ/cm² 70 nm 86 nm 5.5 nmExample 4-16 R-16 105° C. 45.0 mJ/cm² 70 nm 84 nm 5.2 nm Example 4-17R-17 105° C. 45.0 mJ/cm² 70 nm 90 nm 5.0 nm Example 4-18 R-18 105° C.41.0 mJ/cm² 70 nm 86 nm 5.2 nm Example 4-19 R-19 100° C. 42.0 mJ/cm² 75nm 80 nm 5.1 nm Example 4-20 R-20 105° C. 44.0 mJ/cm² 70 nm 92 nm 5.2 nmExample 4-21 R-21 105° C. 41.0 mJ/cm² 70 nm 89 nm 5.2 nm Example 4-22R-22 105° C. 42.0 mJ/cm² 70 nm 90 nm 5.0 nm Example 4-23 R-23 105° C.40.0 mJ/cm² 70 nm 86 nm 4.8 nm Example 4-24 R-24 120° C. 41.0 mJ/cm² 70nm 87 nm 5.4 nm Example 4-25 R-25 105° C. 43.0 mJ/cm² 70 nm 89 nm 5.1 nmExample 4-26 R-26 120° C. 42.0 mJ/cm² 70 nm 85 nm 5.2 nm Example 4-27R-27 105° C. 43.0 mJ/cm² 70 nm 84 nm 4.8 nm Example 4-28 R-28 105° C.43.0 mJ/cm² 70 nm 89 nm 4.7 nm Example 4-29 R-29 105° C. 45.0 mJ/cm² 70nm 86 nm 5.3 nm Example 4-30 R-30 105° C. 40.0 mJ/cm² 70 nm 84 nm 5.1 nmExample 4-31 R-31 105° C. 41.0 mJ/cm² 70 nm 85 nm 5.2 nm Example 4-32R-32 105° C. 40.0 mJ/cm² 70 nm 84 nm 5.0 nm Example 4-33 R-33 105° C.41.0 mJ/cm² 70 nm 85 nm 5.0 nm Example 4-34 R-34 105° C. 43.0 mJ/cm² 70nm 89 nm 5.0 nm Example 4-35 R-35 105° C. 46.0 mJ/cm² 70 nm 92 nm 5.2 nmExample 4-36 R-36 105° C. 45.0 mJ/cm² 70 nm 86 nm 5.1 nm Example 4-37R-37 105° C. 46.0 mJ/cm² 70 nm 88 nm 5.2 nm Example 4-38 R-38 105° C.44.0 mJ/cm² 70 nm 88 nm 4.9 nm Example 4-39 R-39 105° C. 47.0 mJ/cm² 70nm 92 nm 5.2 nm Example 4-40 R-40 105° C. 47.0 mJ/cm² 70 nm 92 nm 5.1 nmExample 4-41 R-41 105° C. 50.0 mJ/cm² 70 nm 94 nm 5.2 nm Example 4-42R-42 105° C. 42.0 mJ/cm² 70 nm 88 nm 5.0 nm Example 4-43 R-43 105° C.44.0 mJ/cm² 70 nm 90 nm 5.1 nm Example 4-44 R-44 105° C. 41.0 mJ/cm² 70nm 90 nm 4.8 nm Example 4-45 R-45 105° C. 45.0 mJ/cm² 70 nm 92 nm 5.0 nmExample 4-46 R-46 105° C. 45.0 mJ/cm² 70 nm 93 nm 5.0 nm Example 4-47R-47 105° C. 48.0 mJ/cm² 70 nm 96 nm 5.1 nm Example 4-48 R-48 105° C.41.0 mJ/cm² 70 nm 86 nm 5.0 nm Example 4-49 R-49 105° C. 42.0 mJ/cm² 70nm 89 nm 5.2 nm Example 4-50 R-50 105° C. 40.0 mJ/cm² 70 nm 88 nm 4.9 nmExample 4-51 R-51 105° C. 44.0 mJ/cm² 70 nm 91 nm 5.2 nm Example 4-52R-52 105° C. 43.0 mJ/cm² 70 nm 92 nm 5.1 nm Example 4-53 R-53 105° C.47.0 mJ/cm² 70 nm 94 nm 5.2 nm Example 4-54 R-54 105° C. 40.0 mJ/cm² 70nm 85 nm 4.8 nm Example 4-55 R-55 105° C. 41.0 mJ/cm² 70 nm 88 nm 5.0 nmExample 4-56 R-56 105° C. 39.0 mJ/cm² 70 nm 88 nm 4.6 nm Example 4-57R-57 105° C. 42.0 mJ/cm² 70 nm 90 nm 4.8 nm Example 4-58 R-58 105° C.42.0 mJ/cm² 70 nm 90 nm 4.8 nm Example 4-59 R-59 105° C. 44.0 mJ/cm² 70nm 93 nm 5.0 nm Comparative Example 3-1 R-60 110° C. 38.0 mJ/cm² 80 nm78 nm 7.8 nm Comparative Example 3-2 R-60 105° C. 45.0 mJ/cm² 70 nm 88nm 8.8 nm Comparative Example 3-3 R-61 105° C. 38.0 mJ/cm² 75 nm 84 nm7.1 nm Comparative Example 3-4 R-62 105° C. 37.0 mJ/cm² 80 nm 76 nm 5.5nm

It is seen from the results of Table 7 that the resist compositionswithin the scope of the invention have improved resolution and minimizedLER when processed by ArF excimer laser lithography. The data ofComparative Examples in Table 7 reveal that prior art resistcompositions satisfy either one or none of resolution and LER. It hasbeen demonstrated that resist compositions comprising polymerscomprising recurring units derived from the lactone-containing compoundsof the invention are improved in resist properties over the prior artresist compositions.

Japanese Patent Application No. 2006-206233 is incorporated herein byreference.

Although some preferred embodiments have been described, manymodifications and variations may be made thereto in light of the aboveteachings. It is therefore to be understood that the invention may bepracticed otherwise than as specifically described without departingfrom the scope of the appended claims.

1. A polymer comprising recurring units derived from alactone-containing compound having the general formula (1):

wherein R¹ is hydrogen, fluorine, methyl or trifluoromethyl, R² and R³are each independently a straight, branched or cyclic monovalenthydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bondtogether to form an aliphatic hydrocarbon ring with the carbon atom towhich they are attached, R⁴ is hydrogen or CO₂R⁵, R⁵ is a straight,branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atomswhich may have a halogen or oxygen atom, W is CH₂, O or S, with theproviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ whenW is O or S, and k¹ is 0 or
 1. 2. A polymer comprising recurring unitshaving the general formula (2):

wherein R¹ is hydrogen, fluorine, methyl or trifluoromethyl, R² and R³are each independently a straight, branched or cyclic monovalenthydrocarbon group of 1 to 10 carbon atoms, or R² and R³ may bondtogether to form an aliphatic hydrocarbon ring with the carbon atom towhich they are attached, R⁴ is hydrogen or CO₂R⁵, R⁵ is a straight,branched or cyclic monovalent hydrocarbon group of 1 to 15 carbon atomswhich may have a halogen or oxygen atom, W is CH₂, O or S, with theproviso that R⁴ is CO₂R⁵ when W is CH₂, and R⁴ is hydrogen or CO₂R⁵ whenW is O or S, and k¹ is 0 or
 1. 3. The polymer of claim 1, furthercomprising recurring units having at least one of the general formulas(3) to (6):

wherein R¹ is as defined above, R⁶ and R⁷ are each independentlyhydrogen or hydroxyl, X is an acid labile group, Y is a substituentgroup having a lactone structure different from formula (1), and Z ishydrogen, a fluoroalkyl group of 1 to 15 carbon atoms or afluoroalcohol-containing substituent group of 1 to 15 carbon atoms.
 4. Aresist composition comprising the polymer of claim 1 as a base resin. 5.A process for forming a pattern comprising the steps of applying theresist composition of claim 4 onto a substrate to form a coating, heattreating the coating, exposing the coating to high-energy radiation orelectron beam through a photomask, optionally heat treating the exposedcoating, and developing it with a developer.